We are making quite a lot of progress with the nipping. She seems to be in a real learning mode now that she's feeling so well. She knows to stop what she's doing when I say no and leave it.
I've been working with my son and see that part of the problem is Sunni is crazy about him and just wants some attention, but he's anxious/nervous with her..might be my fault for saying to be very very careful with her. I've gotten on the floor and held Sunni and Matt sits in front of us and pets her head. When I let her go she goes into his lap and curls up. My son loves that. So he's now getting used to holding her, and she's getting his attention. When he gets up to walk, he's learned to stop walking and say no biting. Its not perfect but he's good about being consistent with her. I have total faith in both of them to work this out, lol.