Bring your interface up on pfsense, give it a network that does not overlap your lan network. Are you really using a /16 on your lan?? Seems bit much.. So lets say create 192.168.10/24 on your other interface (opt1) and you call this wifi or something.
Then connect your AP to this interface.. If you want other ssids to be on different vlans. Then you would create vlans on pfsense, assign them to the interface (em2?) Then on your AP create the other SSIDs using the same vlan ID, lets call it 100 that you used when you created the pfsense vlan.
That really is all there is too it. Other than creating rules on your opt and any vlan interfaces that allow the traffic you want. And enabling dhcp on the interface and vlan interfaces as you see fit.
Why would you try creating a bridge? You would have ZERO reason to do this, and if you wanted your AP or specific ssid of your AP to be on your lan network then connect your AP to your switch..