I have no idea who the manipulator is at the end, but it must be the tie-in to the main villain in E7...
I was dreading that they were going to canonize a much-heralded character from the EU, but the dialogue did not match up with previous presentations of that character. I now think that it is someone we've seen before, in the movies, but whose identity is going to remain hidden for a while longer. It doesn't seem like this mystery character lines up with anyone whom we know of in Ep 7, but there really isn't much to go on.