Well..I'm a Grammie, currently puppy sitting a 11 week pup during the day. It's hard! Lol..but already better! Personally, I think once your skin baby is sleeping through the night..why not? There will be the usual puppy shark biting..but the bully should be well past that stage by the time your skin baby is moving on the ground.
I don't think your crazy at all, Jill. Far far fom it. Planning is good. But..sometimes life goes in a totally odd direction. You will make it work.