Quote Originally Posted by Omecle View Post
Nomura already said they're not related in anyway to Riku, Sora and Kairi.
Hey look a new interview:

Famitsu: You said that none of the iron-clad characters of the secret movie were Roxas or Sora.
Nomura: That is correct. However they are related to one or more characters we have already introduced. Please speculate and look forward to it as well as the new project.

Here's the link: http://www.kh2.co.uk/?page=NI/Famitsu-3