I think that unless you are endangering the welfare of your child that he will not get full custody. Custody will be decided on what is best for the child and if you have been the support structure then I don't see the judge changing. Your stbx has withdrawn himself from seeing your son by his choice.
As for your teen DD, well as a teen the courts understand that they think freely and your having called the cops can easily be seen as a Mom concerned for her DD and upholding behavioral boundaries. It shows an active parent.
I'd get with an attorney and let them help you navigate this circus. I believe that nothing big will change.AKA Moo
Think of the haters in your life as sandpaper; they’ll scratch you up time and time again but in the end you’re polished, smooth, and spotless..while they end up useless
There are shortcuts to happiness, and dancing is one of them-Vicky Baum