If she's playing tug of war and it's the play growl. Then no, don't stop. Sounds like that's her play growl. I didn't know she was such a munchkin. The bath issues will probably be grown out of as long as you're consistent with bath time and reward her for good behavior and trying as hard as you can to ignore the bad behavior.
Don't get your hopes down, we got Giz young too and we've had some obstacles with training hi. mEven today we had a set back and he's almost 6 months old.
But I would definitely try using treat during bath time. Especially if they are the treats you use for training.
Good luck!
By the way if the growling during playing is mean. I would drop the toy and turn away from her. She won't like the lack of attention and will probably stop the growling, that is if it's aggressive growling.