More like her attorney should talk to the principal. If the Union is useless, she could make enough noise to get his ass bagged.
The thing with attorney's is what problem is it going to solve? The attorney can't actually get her job back and can't force the principal to give a glowing recommendation.
The best advice I can give you so she can get back in is to sub. She needs to get to know exactly what a school is looking for and subbing is the best way to do this.
Already have her going down that path. Interim job postings as well. My real hope is that a position will open up after a month or two - new baby, move to another state, etc.. Then she can slide right in.