I'm pretty sure DC is Cain's wrestling coach so Cormier would probably have a slight advantage. It's almost a certainty that this fight will never happen
in the UFC on Fox post-fight presser, Dana said (I paraphrase) he was glad to know Velasquez and Courmier had been talking about fighting each other, and Courmier said he'd fight whoever the UFC told him to, even Velasquez, but that he didn't feel 'this performance warranted a title shot'.
Haven't heard from Vealquez, from Courmier seems willing, and Dana isn't indicating they've flat-out refused, as some teammates have in the past.
But assuming everybody keeps winning, JDS vs DC, Werdum vs Velasquez, then winner vs winner.
The first UFC Heavyweight Grand Prix.