Personally, I would have gone with original designs, than plain old RTP. But, then again it's an easier starting point.
As long as you're respriting everything onto HK, might as well change the palette and shading (the RTP palette could use saturation honestly), and I dislike the mirrored effect that the hair has. You probably should reshade it from a light source (upper right is always common, as far as I can remember).