In the order you listed for the problems here.
- more info about mikrotik config is needed. Can you post an export with the “hide-sensitive” option?
2 and 3) I’m not comfortable enough with vlans on Mikrotik to do anything more than refer you to someone that knows more than me. http://forum.mikrotik.com/t/using-routeros-to-vlan-your-network/126489/1
- yes. You could consider a hEX poe or hEX poe lite and simply bridge all ports with no routes or firewall/nat rules in the hEX. The same product is available as the PowerBox (hEX poe lite) or PowerBox pro (hEX poe). Each PowerBox is the same hEX board indicated but is instead sold inside of a weatherproof enclosure. Be sure to consider power needs. The lite will be cheaper but also cannot output as much power via poe.