I don’t think anyone is jumping on you FCCDAD about anything. It 's a top spot you are in. Just saying that whether you share your info with your DD or not, if she sees her mother’s info, and what the school will be giving her, she and her mother , and whoever else see the info, can deduce your numbers without a whole lot of know how. So the confidentiality isn’t going to be complete. Exact breakdowns, no, but what the schools expect YOU to pay, yes.
You did mention a legal obligation to split the cost with the mother for college somehow, as part of the decree, and that could be reason for more litigation. Anything can be reason for litigation to the litigious, as you probably well know.
I don’t think starting another family was foolish, nor do I feel you are being mean spirited about what you are and aren’t willing to do. Just wishing you good luck in all of this. Looks like your daughter has some good choices. I hope all works out smoothly.