I keep a breeding pair of convicts, along with a salvini and senegal birchir and two pictus cats in my 60gal planted. Everyone gets along just fineas was mentioned before, careful aquascaping and hiding places for everyone, and everything should be fine
as long as the poly dosnt try and hide in the cave the cons are breeding in.
Gourami's are active and do will do well with them too if you havent decided yet.. not capable of hurting your bichirs and unlikely to be swallowed even when they are small.. they also do a good job at scavenging and they are entertaining to watch