Mike, one question for you. You said that you think I have her between a rock and a hard place.
If I was a L and had your case, I would be licking my chops. If it is happening as you say there's no way a judge will award custody of those kids to your W. Keep documenting, let her do what she is doing. She is hanging herself. DO NOT SHOW YOUR CARDS BEFORE THE LAST HAND IS DEALT.
She continues to think she is in control of the sitch and let her think so.
I think you're in good shape no matter what you decide to do. Especailly the legal side of things.
I would not let her take those kids out of the house. Talk to your L about this.