I think most of the environmental concerns could be ignored, thanks to the level of tech in Trek. The Benzites went from needing a breathing device to not needing one in just a few years. Surely Starfleet's gifted engineers can do even better, particularly for species that have been in the Federation for 200 + years.
This sums my opinion up quite nicely. Besides, temperature differences can be ignored as long as they're not too severe. So species with similar environmental requirements could serve together. Trek tech is very powerful
"In a world of locked rooms, the man with a key is King, and honey you should see me in a crown."
- Jim Moriarty, BBC Sherlock