I know it is legal for me to record her. In my state only one participant has to be informed.
I have seen 2 lawyers though it was 2 years ago.
I don't have a criminal lawyer. It is a decent idea.
The most important thing for me, at least for long-term planning, was documenting everything. When you feel the way we do in these relationships, it can be very hard to remember the order of events, and entire episodes get forgotten. Cause and effect is hard to see clearly. There is often a lot of anxiety, worry, and fear, and that fuzzes up our thinking.
If you are at risk of your wife withholding your kids, that documentation will be critically important. Let's hope it doesn't get to worse-case scenario, but if it does, it will be your word against hers, and you will be in much better shape if you have documentation to back up your words.
Documentation also helped me therapeutically, because I can see things now that were opaque to me while I was in the r/s, and the year or so following our separation. I didn't really notice how severe his paranoia was until I saw it documented and collected together.
The lethargy you feel in a time like this can be powerful. If you can, try to focus on one thing at a time so you don't feel defeated by things.