Ah, that coloured version is really nice. I know the lad will just love it.
As for the Dragon type, I understand where you're coming from. You say Kevin likes fiery Dragons - well that is shown in your picture by the western influences, such as the body structure. As for the horns, westerns tend to be more horny (not in that way) the easterns - though it can sometimes be the reverse that is true. I guess they can make a Dragon look 'mean' as you put it, but I believe they can also make a Dragon look 'cool'. As I've said before, there aren't any really strict rules to drawing Dragons for fun, and so whatever you choose to do cannot really be wrong.
Good work as always.