Can't help with electronics much. Generally you want use EPO glue for the "styrofoam" planes. You can find that easily, or use something called "FoamTac". I've used both to repair one of my planes. The "FoamTac" works great to re-attach separated hinge joints. You can google both. I would post a link, but I'm new here and not allowed yet.
I also use "Foam putty" which is a soft cream like substance that will dry and harden after application. I filled a fairly big hole; placed couple of wooden toothpics across the hole; apply glue to edges and toothpics, then fill in with some bits of styrofoam; apply glue, then more bits of styrofoam. After about filled the hole, apply the foam putty and smooth out with putty knife or regular dinner knife. After it dries, use a sanding block or sandpaper to sand it smooth with an light pressure. Do both sides of hole.
Good luck