There are many ways to get fibreglass (or any other reinforcement you want) into / onto wings, here are 3 :
1) Glass straight on top of a traditional veneered foam wing. Filled with a light coat of bulked-up resin to create smooth surface. Primered then sprayed.
2) Glass underneath veneer of foam wing - can be messy as its a lot of ducks to get in a row, but is easy to finish then with solarfilm etc.
3) Vacuum-bagged foam. Produces glass-like surface that can be painted before the lay up is started to impart colouring onto / into a thin gel-coat
They are probably the most popular. Yours should work fine, just might be a fair bit heavier than they needed to be. You could have gotten away with submersing a spruce spar in the top and bottom surface, then brown-papering over that. To be honest, even that's probably overkill - Chris Goulds gets away with a lot less in his designs that use brown paper and PVA.
If you're not sure on the soldering, don't bother changing them out, but the ESC will probably appreciate at least a little air over it. Maybe a small duct and vent?
As for the tailplane - for that size I'd have used a flat balsa plate and maybe cut some lightening holes in it. Jobs done.
Edited to add : I'm not bashing your design at all, kudos to you for getting it done
I keep trying to save up for an APM 2.5, but other projects or house stuff get in the way