How to insulate garage walls from the outside?
I see no problem with your plan. I asked about vapor barrier in a comment, and since you're not using any that concern is moot. It makes no difference which side you install fiberglass batts from.

I would make a minimal number of strategically-located cuts in the housewrap. If you can cut over lumber you'll be able to tape them (using approved housewrap tape) fairly easily. If you can't, I'd consider installing strips of housewrap across the cuts and taping those edges over framing, where you can press it tight for a good seal. Lap all joints with water flow in mind, of course.