Hideo Kojima has flat out denied having any involvement with The Phantom Pain, in an interview with “Youth Arabia”:
YA: Did you have anything to do with Phantom Pain , since the character bears a resemblance to Solid Snake?
HK: (Laughs) Phantom Pain is being made by Moby Dick studios, I do not have any part in that game. I saw the resemblance there though.
The interview moves from subject to subject quickly, so there’s no followup to this point, unfortunately. But it’s obvious Kojima isn’t just being cheeky here; at this point, he would have to be an out-and-out liar if it turns out he’s involved with the game.
As I said previously, I believe The Phantom Pain is the taboo “Devil Project” which Kojima said had the potential to end his career if people don’t respond well. The Devil/Ogre Project has been shrouded in secrecy from the beginning, although we know that it needs to involve visible demons, and that it’s not Ground Zeroes; manwhile, the trailer for The Phantom Pain includes the question “Am I in hell?” Coincidence? Lying directly to game journalists and fans could certainly backfire, and perhaps it’s is the career-jeopardizing move Kojima has now fully committed to.