Seems pretty good. although I think that, in terms of sprite, it should keep the body parts as you mentioned, however, their colour should be something like grey so as to show that it is a perfect refusion of the dragons and not simply a fusion of body parts which B.Kyurem and W.Kyurem were. This also gives it an appearance of its own rather than botched up prices of others. Also, I’m not sure if it should keep the ice type since that part is solely related to Kyorem (normal) as it was empty and cold (incomplete).