Thank you all for your replies. I guess I just have to bite the proverbial bullet and call my lawyer to give her the information she needs to complete the file. I know I still tend to want to "keep the peace" especially where AH is concerned, because it seems so unpleasant when he goes on the war path. He may be quite able to forgo an appearance to court for the custody of his child, but he won't just take wage garnishment sitting down. Ugh.
As for his ex, that's a can of worms I regret opening, but now that it is, the only thing to do is to go no contact. I initially wanted to keep in touch with her solely because I'd like to keep her contact information current in the event that DD wants to meet one of her half-brothers.