Mutt,
It sounds like your ex is putting the kids in the middle with divorce poison and your staying out of it, which is good. The kids have a right to both parents. I would suggest keeping a journal and writing down her bad behavior with the date and time. That way you can recall her behavior for court if you need it. I hope it doesn't come down to that but you want to keep your ducks in a row like you said. Hang in there.
That is right on... .My lawyer just asked me for some instances of abuse, alienation, etc. I have been keeping a audio journal on my smart phone with a diary app. It is super easy as I just do talk to text. It takes about 2 minutes to do -backs up in the cloud - and was invaluable as I was able to go back as far as 5 years with dates and times and specifics.
Sad thing though is that it did take me 5 years to do something. I bet though if I would have left earlier, my insecurities would have pulled me back into the relationship. It has been hard now cant imagine when I had less resolve.