Thanks for the responses! I feel pretty good about it, and we had them playing today.
The bite inhibition thing I've seen in the last few times she was playing with them. She used to bite and mouth us, which we are discouraging (Tonka! No!) but she's still mighty fond of it - and over the last week, her bite is much calmer when she does so.
It was pretty funny, watching her tug on the hock and jowels of her big brother... and ears... and then they would run away behind the house.
We're pretty good buddies with the neighbors - both moderately young couples, native Minnesotans, etc - so I don't think it will be a problem having access to them.
What could be an issue is when Tonka gets big enough to seriously tussle with her momma, Winona! I've read that genders tend to sort out pack order among each other - so these two girls could be in for it! (and they look so alike - blaze fawns with white feet, little lines up the snout to mid-forehead... it's great...)