He would not have been known as Ganon. He would simply be a demon king who reincarnates into Ganon later on.Aonuma specifically stated Ganon is not in this game. You're looking too far into that picture, it's just some generally demonic looking thing.
They can't pull a TP on you because you know that Ghirahim has a master he wishes to revive. We don't even know if he will succeed or not. I know Ganondorf will not be in SS, but his spiritual predecessor could be.I really doubt that the giant whale is Ghirahim's master. If we remember a while back, it was said that the whale rescued Zelda from Ghirahim's tornado. And it was also already told that Ganondorf would not appear in SS.
I surely hope they doesn't pull a TP on us.