im not sure what you mean. if your baby is fed his last bottle, and happens to fall asleep, of course put him in his crib. if he eats his last bottle, and is still awake, see if the pacifier works. but when you say put him in his crib, then leave the room, does he still need that bottle? when then is he getting that last bottle. are you going to give him less than he is getting now?
aside from that, things are only a "bad habit" if you yourself are defining them as that. letting your baby cry themselves to sleep is not acceptable at all before 6 months. imo, you should never let your child cry themselves to sleep. it is cruel and you are never teaching your child to trust. there are actually quite a few negatives about CIO, but only positive results from comforting a baby to sleep.