I'm guessing very, very low. If they were developing the game, chances are they'd have Hiromichi Tanaka's team working on it - you know, the same ones that JUST finished Final Fantasy XIV and will probably be put to work immediately on patches, expansions and DLC.
I'm thinking it's more likely those mystery titles will be Final Fantasy or Kingdom Hearts spinoffs, or otherwise completely forgettable Eidos games to fulfill SquEnix's belief that they must appeal to Western audiences by making completely generic Western-styled games.