1) Good luck
2) I'd bet your attorney will advise you to not go the "PoS mom" route. Even if she's caught red-handed doing bad things, I'd avoid a situation where she's on trial for being a bad mother, because she'll defend herself more vigorously. I remember when my daughter decided to stay with me full time. I didn't rock the boat at all -- even kept paying child support as if it were a 50/50 arrangement.
3) Good luck!