IIRC, Elektra took over The Hand during Wolvie's Agent of SHIELD arc (directly following his de-brainwashing), I thought. She was pretending to be brainwashed, then trashed their leadership and took over, I think. But since I don't follow daredevil or the like, I may be totally off on that and it may have happened elsewhere.
The most prevalent guess I've heard for the new Ronin, if it's not Matt, is that it's Mr. Castle, following his Civil War appearances. A lot of people think it's gonna be good ole Mr. Rogers, but he's supposed to be elsewhere in the MU around that time...
