I've heard that oil finishes or natural finishes are supposed to be better, that's the reason McCartney sanded off the Fireglo finish on his Ric. But I'd say there are enough cutouts in the body (neck-if bolt on, pickups, electronics etc) that are not sealed that the native wood should be able to resonate properly.
Would there be a difference between gloss and satin? No way. ALL finishes (lacquer, urethane etc, not oil obviously) are gloss, satin or flat finishes simply have flattening agents added. So the finish is exactly the same except for the looks.