The method used for image corrections is simple.
Find what the distortion is by imaging something known like a nice point star. Take that image and figure out where the light went and put it back into that single pixel that it should have been in in the first place.
Then use that process to go through the whole image pixel by pixel and put the light where it should be.
As to making a mirror with epoxy, go do it and see how it works. If you succeed, you will probably be the first to do so.