Combining the two methods certainly wasn’t my intent! I was actually trying to follow yours…but like I said before, I’m just lost at how bridges and VLANs worth together. 
Anyway, I decided to reset my config to factory default and then try to implement what you suggested in your latest post. Unfortunately, it didn’t work…though what did end up happening is that all of the devices on my LAN ended up pulling IP addresses from my ISP, so somehow I must have ended up bridging the LAN and WAN together.
The other note: I’m going to have to go with a hybrid port on the WAP (which is on ether3) rather than a fully trunked port because the UniFi effectively requires its management interface to be on an untagged connection (there are some ways to partially work around that, but it’s more hassle than it’s worth). So I need ether3 to be an access port for VLAN20.
Here’s the factory default config:
[admin@MikroTik] > /export hide-sensitive terse
# jan/02/1970 00:01:15 by RouterOS 6.42.6
# software id = DYMH-RJ3W
#
# model = RouterBOARD 750G r3
# serial number = xxx
/interface bridge add admin-mac=xx:xx auto-mac=no comment=defconf name=bridge
/interface list add comment=defconf name=WAN
/interface list add comment=defconf name=LAN
/interface wireless security-profiles set [ find default=yes ] supplicant-identity=MikroTik
/ip pool add name=default-dhcp ranges=192.168.88.10-192.168.88.254
/ip dhcp-server add address-pool=default-dhcp disabled=no interface=bridge name=defconf
/interface bridge port add bridge=bridge comment=defconf interface=ether2
/interface bridge port add bridge=bridge comment=defconf interface=ether3
/interface bridge port add bridge=bridge comment=defconf interface=ether4
/interface bridge port add bridge=bridge comment=defconf interface=ether5
/ip neighbor discovery-settings set discover-interface-list=LAN
/interface list member add comment=defconf interface=bridge list=LAN
/interface list member add comment=defconf interface=ether1 list=WAN
/ip address add address=192.168.88.1/24 comment=defconf interface=bridge network=192.168.88.0
/ip dhcp-client add comment=defconf dhcp-options=hostname,clientid disabled=no interface=ether1
/ip dhcp-server network add address=192.168.88.0/24 comment=defconf gateway=192.168.88.1
/ip dns set allow-remote-requests=yes
/ip dns static add address=192.168.88.1 name=router.lan
/ip firewall filter add action=accept chain=input comment="defconf: accept established,related,untracked" connection-state=established,related,untracked
/ip firewall filter add action=drop chain=input comment="defconf: drop invalid" connection-state=invalid
/ip firewall filter add action=accept chain=input comment="defconf: accept ICMP" protocol=icmp
/ip firewall filter add action=drop chain=input comment="defconf: drop all not coming from LAN" in-interface-list=!LAN
/ip firewall filter add action=accept chain=forward comment="defconf: accept in ipsec policy" ipsec-policy=in,ipsec
/ip firewall filter add action=accept chain=forward comment="defconf: accept out ipsec policy" ipsec-policy=out,ipsec
/ip firewall filter add action=fasttrack-connection chain=forward comment="defconf: fasttrack" connection-state=established,related
/ip firewall filter add action=accept chain=forward comment="defconf: accept established,related, untracked" connection-state=established,related,untracked
/ip firewall filter add action=drop chain=forward comment="defconf: drop invalid" connection-state=invalid
/ip firewall filter add action=drop chain=forward comment="defconf: drop all from WAN not DSTNATed" connection-nat-state=!dstnat connection-state=new in-interface-list=WAN
/ip firewall nat add action=masquerade chain=srcnat comment="defconf: masquerade" ipsec-policy=out,none out-interface-list=WAN
/ipv6 firewall address-list add address=::/128 comment="defconf: unspecified address" list=bad_ipv6
/ipv6 firewall address-list add address=::1/128 comment="defconf: lo" list=bad_ipv6
/ipv6 firewall address-list add address=fec0::/10 comment="defconf: site-local" list=bad_ipv6
/ipv6 firewall address-list add address=::ffff:0.0.0.0/96 comment="defconf: ipv4-mapped" list=bad_ipv6
/ipv6 firewall address-list add address=::/96 comment="defconf: ipv4 compat" list=bad_ipv6
/ipv6 firewall address-list add address=100::/64 comment="defconf: discard only " list=bad_ipv6
/ipv6 firewall address-list add address=2001:db8::/32 comment="defconf: documentation" list=bad_ipv6
/ipv6 firewall address-list add address=2001:10::/28 comment="defconf: ORCHID" list=bad_ipv6
/ipv6 firewall address-list add address=3ffe::/16 comment="defconf: 6bone" list=bad_ipv6
/ipv6 firewall address-list add address=::224.0.0.0/100 comment="defconf: other" list=bad_ipv6
/ipv6 firewall address-list add address=::127.0.0.0/104 comment="defconf: other" list=bad_ipv6
/ipv6 firewall address-list add address=::/104 comment="defconf: other" list=bad_ipv6
/ipv6 firewall address-list add address=::255.0.0.0/104 comment="defconf: other" list=bad_ipv6
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept established,related,untracked" connection-state=established,related,untracked
/ipv6 firewall filter add action=drop chain=input comment="defconf: drop invalid" connection-state=invalid
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept ICMPv6" protocol=icmpv6
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept UDP traceroute" port=33434-33534 protocol=udp
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept DHCPv6-Client prefix delegation." dst-port=546 protocol=udp src-address=fe80::/16
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept IKE" dst-port=500,4500 protocol=udp
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept ipsec AH" protocol=ipsec-ah
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept ipsec ESP" protocol=ipsec-esp
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept all that matches ipsec policy" ipsec-policy=in,ipsec
/ipv6 firewall filter add action=drop chain=input comment="defconf: drop everything else not coming from LAN" in-interface-list=!LAN
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept established,related,untracked" connection-state=established,related,untracked
/ipv6 firewall filter add action=drop chain=forward comment="defconf: drop invalid" connection-state=invalid
/ipv6 firewall filter add action=drop chain=forward comment="defconf: drop packets with bad src ipv6" src-address-list=bad_ipv6
/ipv6 firewall filter add action=drop chain=forward comment="defconf: drop packets with bad dst ipv6" dst-address-list=bad_ipv6
/ipv6 firewall filter add action=drop chain=forward comment="defconf: rfc4890 drop hop-limit=1" hop-limit=equal:1 protocol=icmpv6
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept ICMPv6" protocol=icmpv6
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept HIP" protocol=139
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept IKE" dst-port=500,4500 protocol=udp
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept ipsec AH" protocol=ipsec-ah
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept ipsec ESP" protocol=ipsec-esp
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept all that matches ipsec policy" ipsec-policy=in,ipsec
/ipv6 firewall filter add action=drop chain=forward comment="defconf: drop everything else not coming from LAN" in-interface-list=!LAN
/system routerboard settings set silent-boot=no
/tool mac-server set allowed-interface-list=LAN
/tool mac-server mac-winbox set allowed-interface-list=LAN
[admin@MikroTik] >
Here’s the config after applying
[admin@MikroTik] > /export hide-sensitive terse
# jul/29/2018 00:24:21 by RouterOS 6.42.6
# software id = DYMH-RJ3W
#
# model = RouterBOARD 750G r3
# serial number = xxx
/interface bridge add admin-mac=xx:xx auto-mac=no comment=defconf name=bridge
/interface vlan add interface=bridge name=if-vlan-lan vlan-id=20
/interface vlan add interface=bridge name=if-vlan-wan vlan-id=10
/interface list add comment=defconf name=WAN
/interface list add comment=defconf name=LAN
/interface wireless security-profiles set [ find default=yes ] supplicant-identity=MikroTik
/ip hotspot profile set [ find default=yes ] html-directory=flash/hotspot
/ip pool add name=default-dhcp ranges=192.168.88.10-192.168.88.254
/ip dhcp-server add address-pool=default-dhcp disabled=no interface=if-vlan-lan name=defconf
/interface bridge port add bridge=bridge comment=defconf interface=ether2 pvid=20
/interface bridge port add bridge=bridge comment=defconf interface=ether3 pvid=20
/interface bridge port add bridge=bridge comment=defconf interface=ether4 pvid=20
/interface bridge port add bridge=bridge comment=defconf interface=ether5 pvid=20
/interface bridge port add bridge=bridge interface=ether1 pvid=10
/ip neighbor discovery-settings set discover-interface-list=LAN
/interface list member add comment=defconf interface=bridge list=LAN
/interface list member add comment=defconf interface=ether1 list=WAN
/ip address add address=192.168.88.1/24 comment=defconf interface=bridge network=192.168.88.0
/ip dhcp-client add comment=defconf dhcp-options=hostname,clientid disabled=no interface=if-vlan-wan
/ip dhcp-server network add address=192.168.88.0/24 comment=defconf gateway=192.168.88.1
/ip dns set allow-remote-requests=yes
/ip dns static add address=192.168.88.1 name=router.lan
/ip firewall filter add action=accept chain=input comment="defconf: accept established,related,untracked" connection-state=established,related,untracked
/ip firewall filter add action=drop chain=input comment="defconf: drop invalid" connection-state=invalid
/ip firewall filter add action=accept chain=input comment="defconf: accept ICMP" protocol=icmp
/ip firewall filter add action=drop chain=input comment="defconf: drop all not coming from LAN" in-interface-list=!LAN
/ip firewall filter add action=accept chain=forward comment="defconf: accept in ipsec policy" ipsec-policy=in,ipsec
/ip firewall filter add action=accept chain=forward comment="defconf: accept out ipsec policy" ipsec-policy=out,ipsec
/ip firewall filter add action=fasttrack-connection chain=forward comment="defconf: fasttrack" connection-state=established,related
/ip firewall filter add action=accept chain=forward comment="defconf: accept established,related, untracked" connection-state=established,related,untracked
/ip firewall filter add action=drop chain=forward comment="defconf: drop invalid" connection-state=invalid
/ip firewall filter add action=drop chain=forward comment="defconf: drop all from WAN not DSTNATed" connection-nat-state=!dstnat connection-state=new in-interface-list=if-vlan-wan
/ip firewall nat add action=masquerade chain=srcnat comment="defconf: masquerade" ipsec-policy=out,none out-interface-list=if-vlan-wan
/ipv6 firewall address-list add address=::/128 comment="defconf: unspecified address" list=bad_ipv6
/ipv6 firewall address-list add address=::1/128 comment="defconf: lo" list=bad_ipv6
/ipv6 firewall address-list add address=fec0::/10 comment="defconf: site-local" list=bad_ipv6
/ipv6 firewall address-list add address=::ffff:0.0.0.0/96 comment="defconf: ipv4-mapped" list=bad_ipv6
/ipv6 firewall address-list add address=::/96 comment="defconf: ipv4 compat" list=bad_ipv6
/ipv6 firewall address-list add address=100::/64 comment="defconf: discard only " list=bad_ipv6
/ipv6 firewall address-list add address=2001:db8::/32 comment="defconf: documentation" list=bad_ipv6
/ipv6 firewall address-list add address=2001:10::/28 comment="defconf: ORCHID" list=bad_ipv6
/ipv6 firewall address-list add address=3ffe::/16 comment="defconf: 6bone" list=bad_ipv6
/ipv6 firewall address-list add address=::224.0.0.0/100 comment="defconf: other" list=bad_ipv6
/ipv6 firewall address-list add address=::127.0.0.0/104 comment="defconf: other" list=bad_ipv6
/ipv6 firewall address-list add address=::/104 comment="defconf: other" list=bad_ipv6
/ipv6 firewall address-list add address=::255.0.0.0/104 comment="defconf: other" list=bad_ipv6
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept established,related,untracked" connection-state=established,related,untracked
/ipv6 firewall filter add action=drop chain=input comment="defconf: drop invalid" connection-state=invalid
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept ICMPv6" protocol=icmpv6
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept UDP traceroute" port=33434-33534 protocol=udp
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept DHCPv6-Client prefix delegation." dst-port=546 protocol=udp src-address=fe80::/16
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept IKE" dst-port=500,4500 protocol=udp
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept ipsec AH" protocol=ipsec-ah
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept ipsec ESP" protocol=ipsec-esp
/ipv6 firewall filter add action=accept chain=input comment="defconf: accept all that matches ipsec policy" ipsec-policy=in,ipsec
/ipv6 firewall filter add action=drop chain=input comment="defconf: drop everything else not coming from LAN" in-interface-list=!LAN
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept established,related,untracked" connection-state=established,related,untracked
/ipv6 firewall filter add action=drop chain=forward comment="defconf: drop invalid" connection-state=invalid
/ipv6 firewall filter add action=drop chain=forward comment="defconf: drop packets with bad src ipv6" src-address-list=bad_ipv6
/ipv6 firewall filter add action=drop chain=forward comment="defconf: drop packets with bad dst ipv6" dst-address-list=bad_ipv6
/ipv6 firewall filter add action=drop chain=forward comment="defconf: rfc4890 drop hop-limit=1" hop-limit=equal:1 protocol=icmpv6
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept ICMPv6" protocol=icmpv6
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept HIP" protocol=139
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept IKE" dst-port=500,4500 protocol=udp
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept ipsec AH" protocol=ipsec-ah
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept ipsec ESP" protocol=ipsec-esp
/ipv6 firewall filter add action=accept chain=forward comment="defconf: accept all that matches ipsec policy" ipsec-policy=in,ipsec
/ipv6 firewall filter add action=drop chain=forward comment="defconf: drop everything else not coming from LAN" in-interface-list=!LAN
/system routerboard settings set silent-boot=no
/tool mac-server set allowed-interface-list=LAN
/tool mac-server mac-winbox set allowed-interface-list=LAN
[admin@MikroTik] >
After applying that, my clients get new IP addresses issued directly by the ISP and can no longer communicate with the router, so I’m clearly screwing something up! I don’t know how, though because the clients should all be on VLAN 20 (if-vlan-lan) and shouldn’t be able to talk directly to VLAN 10. Again, I’m just missing a mental link somewhere with how the bridge plays with VLANs on the MT platform.
I really do appreciate your patience with my obvious stupidity, here!