It would also be correct to leave out the translation for "well", since it would be assumed that "they are behaving well" when you leave it out.
Yep. Same is true in Dutch, you can also omit the word "goed".
wij gedragen altijd goed, I guess this is possible if not. Would anyone tell me why not.
It needs to be "wij gedragen ons", or literally, "we behave ourself". Gedragen is a reflexive verb and so always needs a matching reflexive pronoun, ourself, yourself, etc.