Responsible stockings are based on adult sizes, not the tiny babies bought from local breeders or fish stores.
Your shark will reach ~15cm and have some attitude, hence the 4-foot tank requirement.
Your Mollies will reach ~12cm and could be a bit fiesty, will sink you with fry if a male/female pair, hence the 3-foot tank requirement.
Your BN Catfish will reach ~15cm, two males could get fiesty with each other, a pair will sink you with fry. Plus they are "poop machines" of the highest order.
Your Firemouths will reach ~15cm and all hell will break loose in that tank if they breed.
You have no room.
Buying fish that will outgrow current tanks is very dangerous, good intentions of that mystical upgrade can fail to happen for all sorts of reasons.