When you say American Tree Frogs I'm thinking American Green Tree Frogs and are anolies the same as Anoles cuz i googled and it says do you mean anoles... just so I know if im thinking of the right animals.

also yes you could fit 4 (of the same) tree frogs in a 44 gal. terrarium just have lots of hiding spots for them to feel safe..... but you are mixing species in the same terrarium thats where I fear the extra stress.

But I could be wrong im going by what ive read here.