I still believe he is concerned with his image (and hasn't lost his job despite dom viol arrests) far too much in true NPD fashion to seriously hurt me.
That said I am taking every precaution I can think of but I am not sure what more I can do
Been there. Arm yourself with a pitbull lawyer and an excellent therapist.
As a true NPD he may not hurt you irreparably, but he will dance on that line as long as you have his attention, and claim provocation and ignorance to every authority to try to eke out of taking responsibility for his games.
NPD guys mess with people who have poor boundaries. He's got the law on his side, kind of, but that won't last forever, like you have observed. You do have to be vigilant... but it's exhausting. Get your lawyer on board -- or get a new lawyer. Lean on your therapist.
I know I've said it before but I spent a decade freaked out by my ex and all his craziness, and my family "support system" turns out to be self-invested and not at all supportive of what's best for me and the kids. It wasn't until I got serious about SR/Al-Anon recovery and dove into therapy and learned how to maintain my personal boundaries that it all snapped into clarity. It wasn't any one thing, I think, but individual counseling to help me draw lines around my AH, my NPD ex, and my nutso family of origin, and for the first time see clearly what was their responsibility and what was mine.