(A) Yes, the wing is a 2-piece set up. Each panel slides onto a wing tube.
(B) Each control surface is pretty large, and it of course would depend on how fast you fly it around, but I would say that 70-75 oz/in at a minimum on the elevator and rudder.
(C) Wheels are foam, 4 inches in diameter.
(D) I don't have any experience with the G38, but I would guess that you'll have to cut the cowl to accommodate the muffler and/or carb. I'm using a ZDZ 40 with a rear mounted carb and a pitts-style muffler. I had to open the left side of the cowl to make room for the muffler. (see photo below)
(E) Considering that I paid $630 from my local hobby shop, I'd say that $530 is a good price, especially if floats are included.