First order of Business: Spend the time to find all of the parts from the wreckage, this will save you a lot of time.
Next item: Put the "Puzzle" back together with C/A ( including wicking some C/A into any cracks). The C/A doesn't give you any strength, it's just there to hold everything together in the proper alignment.

Scrape the Paint off of a Fuse, much quicker and less "messy" than sandpaper.

Plan on using Laminating Epoxy for repair , it will bond to and cure over Epoxy or Polyester .

Even if you can "fix" a fuse from the inside I would still put a layer of glass on the outside of the fuse. It's much stronger and after sanding and fairing you will probably be the only person who will be able to spot the repair.

Jim B