Please don't rehome him. At his age, it will be a major stress on him. You have to think is it worth it to rehome him at this age?
Muzzling your dog and forcing him to interact with your daughter will make things worse. It will stress him out and scare him even more, and now he'll feel like he can't defend himself. Then one day when the muzzle's off, he'll skip his warning and go straight to bite.
For now, heed his warnings. A growl is communication, the same as you saying "Don't do that, I don't like it" or "You're scaring me, back up." It's the only way dogs have to tell us something is making them uncomfortable.
Have your daughter feed him treats and talk calmly to him but don't force anything on him. If nothing else, in time he should learn that she's okay and he has no reason to be worried. Don't let them be together unsupervised.