looks about right, use some stiff wood for some stringers down the fuz and spars, the rest should be nice and light.
engine, ummm 15-25 should be about right, all mini gear, micro on the throttle.
it reminds me of the japanese plane, K something, komoro? i dunno, Cartman will, also much like the Fun15...
keep it light, have fun building and even more flying YOUR design