70-73 RS Endura Noses

[CamarosRus]

I'm prepping a very good used 70-72 Camaro Urethane Nose. Sanding off old OE paint down to "Orange" base material using a DA sander and 100 grit paper.
On back side of nose there is some areas that have split open or apart from the steel
frame. I'm running a cut-off wheel down in the opening to try and clean out rust and dirt
Urethane still very soild, no delam, no bubbling.

1) Can I use a liquid paint stripper down in that recessed area where the grill surround sits
2) What urethane patch/filler material should I buy to fill the open crack
3) Does the bodyman/painter use epoxy as a base coating over the urethane
or something different??
4) What value might be put upon a NOS nose in 2020????