Welcome!
Crayfish eat small fish and even some bigger ones. Can exist in a larger tank with a special area to call their own, will probably fight each other for territory too. Probably not a good creature for your tank.
Try a CPO Cambarellus patzcuarensis Orange if you like the crayfish. Or some prefer Cajun dwarf cray - Cambarellus Shufeltii
Welcome to AA!.
The other fish are nice! Love the snail, but I understand they eat live plants. I haven't had one personally though.
Maybe the crayfish and the snail can go to a different tank with some fast growing Elodea.