Maybe they could put her in the junior room for a bit and see if that helps. With the amount of stress the family has been under keeping one thing constant will help her. I'd push to put her back in the junior room.

I would talk to the teachers about the "not my friend bit" As a teacher I would want to talk to the kids about this and how it makes people feel.

Right now my DD#1 is going to the 2-4 year old Sunday School class instead of the K-2. Because the thought changing classes was getting her upset. We just moved and will give her time to settle before moving her up.