Well Famitsu seems to have an in with Square Enix, I'm sure they know more than they are allowed to say. Notice how they didn't even ask about a XIV? XIV: ARR is out X HD is out. Only things in development right now, or should be, are KH 2.5 and KH 3 and XV. Curtain call is coming out soon in japan, nothing left there. Unless they are super focused on those games, which I doubt since if they were we'd have XV already, than they HAVE to be doing something else. Be it X-3 like you're saying DMKA or they are working on XIV, which I still think has something to do with Agni's Philosophy
,the tech demo they released back in 2012. That thing had wayyyyy too much art direction and character development for a freaking tech demo. YOU CAN'T FOOL ME SE.