First of all, assuming you are using vlans please read this reference: http://forum.mikrotik.com/t/using-routeros-to-vlan-your-network/126489/1
One bridge for each device.
Second device gets its IP from the management vlan
Only the management vlan need be identified
Only the management vlan is tagged on the bridge for /interface bridge vlan settings.
Best thing for you do to is show your requirements
a. identify all the users/devices (internal, external including admin)
b. identify what traffic flow each require
c. provide a network diagram of equipment being used, ports, vlans etc…
Lastly after creating a plan, and attempting a config, post it here for review
/export file=anynameyouwish (minus router serial number, any public WANIP information, keys)