No, there isn't any release date at the moment. It is unlikely that Nintendo will say anything at all; they will probably just do something like they did in Gen 5. They just release the Dream World, and people find the Pokemon with the Hidden Ability there.
Of course, there is no proof that they will be released at all. Look at what happened to Chandelure; everyone was hyping Shadow Tag and hoping that it would be released. And then, Game Freak decides to disappoint us and makes its Hidden Ability Infiltrator in the new Gen.