My brother owns a detail shop. Long and short, he sees oxidized lenses all day long. Never has he recommended wet-sanding them, let alone with 400 grit. A high speed buffer with a bit of scratch removing product, followed by a simple polish works great. Plus, its less than 5 minutes per headlight, max, even if you mask off the paint to keep splatter down.

Your results look good, but the pics still show a bit o haze even after the re-install.

Worst case, he might do a quick 2000 grit wet sand, then the above mentioned steps.

Granted, a typical guy won't have a high speed buffer (quite different than an orbital), but maybe that's why we should all know a decent detailer....