The corrosion is coming up from the back, a few of the spots it has not yet perforated the base coat. At a bare minimum, the metal around the pinch seam is going to have to come off. If I can find a good piece at the wrecker I will cut it off and reattach it with structural adhesive.
You won't get very good results feathering the clear and blending new clear into it. You could do something like that but to have it come out decent you'll need to feather, then scuff the whole panel, blend new base coat past where you feathered, then clear the whole panel.
Been doing some reading online and everything seems to concur with what you've said. I guess I just hate the idea of taping around the urethaned in rear windshield and quarter window because I have fixed too much peeling clear coat on jobs done by other backyard hacks.
