That's not what Gabranth is saying. He is stating that Riku never became a Heartless, and thus could not have a Nobody. You can't just become a Heartless of gain a Nobody if you semi-immerse yourself in Darkness. That completely goes against everything KH has been trying to explain within the second installment.

That goes for your 'theory' too. You can't gain either if you haven't lost your Heart. Ansem the Wise, so we know, never lost his. If he did, then the Ansem we see in 2 would have been a Nobody, due to the fact he has memory of everything. And to further disprove your theory, he can't even be a Nobody (that being the only alternative), because he mentioned himself that he was consumed with rage, which is blatantly an emotion; something which Nobodies cannot experience.

Xehanort is indeed back in darkness, doesn't mean he's dead neccesarily because heartless are darkness itself so Xehanort can just keep coming back.

Hm... Nomura said Kingdom Hearts is Sora's story, NOBODY ELSE'S, so it takes out the possibly of this being a prequel. And also, that Roxas look-alike? Have you forgotten that Roxas was made during the time Sora became a Heartless in the original KH? And more info on Nobodies had been revealed in CoM and KHII. And in order for Sora to wake up, Roxas had to fuse with him.

Besides, how the Hell are he and Namine going to have their own bodies if they were entities from other people's hearts? Though I know Namine had Kairi's memories, Roxas never had Sora's (except he dreams of it), so that scratches out the possibility of the Nobodies being involved (especially because there is nothing that remains of Organization XIII anymore).

Nomura also said that the armored people ARE connected to Sora, Riku, and Kairi but he didn't say how, specifically (he also did point out that Sora and co. are not blood-related to them). So therefore, no prequel.

And he didn't even revealed the armored people's names yet!

This is also continuing where KHII left off. Remember, when KHII ended, Sora gets a letter from King Mickey...

And yes, Mickey is the fifth Keyblade wielder. And also, it is a possibility that the old guy is Xehanort, like everyone else said. It may look like he may've been dead in Original KH, but... Wasn't Xehanort a heartless or something like that? Since heartless is darkness itself (and they did make their reappearance in CoM AND KH II), he could just keep coming back.

My point exactly. Since Xehanort is of darkness itself he is an eternal being that can keep coming back whenever he feels it is inconvinient for everyone else. Basically we have another Sephiroth xD. Go Figure