Hmm you say that Tsukiyomi is a part of the mange sharingan and Amaterasu is supposed to be even more powerful, how about that three-super-attack theory one genjutsu, ninjutsu and tai-jutsu, he has showed us the first two now we're waiting on an awesome tai-jutsu.. If your theory is correct then I wonder which technique he used on all the Uchiha's (parents, clan members) etc.. probably the powerful one.