Have to resurface a pool and not sure whether to do plaster or fiberglass.

You should be fine with any mid-tear drop in bathtub... fiberglass... cast iron... they each have their benefits and draw backs.

I like crawl space houses here for that reason unless I'm living in it and want the extra tornado protection.Regarding the wiring comment, yes you can just run the grounds together because they go to the same place ultimately but there aren't enough outlets and the wiring is fiberglass insulated and by now has crumbled away in this climate.

This iso board is several inches thick (styrofoam type product which is covered on both sides with a fiberglass type material).

I personally think it is ridiculous that as a homeowner that you cannot do things like add fiberglass insulation to walls.

Insulation - fiberglass, spray foam, etc5.

Personally, I loathe fiberglass.

They are just fiberglass maybe 1/4 thick,  3 feet high with a reflector on the end and you push them in the ground to mark the boundary. 

However that is simply one material that has many advantages over engineered materials such as common fiberglass batt insulation.

Just looking to swap out one fiberglass shower for another?