I'd start with option 3. And line the inside of the fiberglass part with that Kevlar/silica stuff from Aircraft Spruce. If you can't increase the clearance (and you can't increase the clearance without either moving the pipe, squashing the pipe, or cutting away fiberglass) then you have to keep the heat from going across the narrow gap between the pipe and the bodywork. Multiple shields will work better than one, especially if there is an air gap between them.
The only other option I can think of is to remake the bodywork so that the curve and lip is duplicated, but further away from the pipes. In order to do that, you'd have to cut a strip out of that area all the way around, for example an inch wide, then remold the lip, sand and refinish the entire area which is black. A LOT of work, and headaches. I think I'd fit multiple shields first and see what happened.
Note that when the weather gets warm, this problem may return, unfortunately. Or maybe the ambient temp won't make that much difference. I hope it doesn't.