No...as INDYJon22 pointed out, there is too much wrong with the way it has played out so far for it to be Cole. The personality is wrong, the timing is wrong, and Cole is way too public each RAW to conceivably secretly write the emails WHILE announcing. Now, obviously, there are no real emails, if you noticed, he always has a small cue card with him telling him what to say, as the contents of the "email" would have been written out ahead of time in order to plan for the storyline...That's real world. In the kayfabe world, Everyone behind Cole can see what he is doing all RAW. Certainly, Lawler would notice...you would think they would have Lawler say something like "Cole, why are you always checking your cell phone" or something like that. The tweener to face content of the emails, helping the face out more than the heels is a problem too. Cole is in the middle of a full heel turn. If you are going to claim collusion on the part of Cole and DB, that their "feud" is a kayfabe work, you need to show at least a little evidence to support it, because right now, it makes absolutely zero sense. I am not saying you are flat out wrong, merely that I remain unconvinced, having seen nothing at all to support that claim.
More likely, it will be someone completely off camera. Triple H would be a decent choice, since it implies that even if he hasn't been seen on TV for months, he is still involved. (talking about his character, not the real world, where we all know he was hurt, got better, filmed a movie, got hurt again). Triple H being the GM could explain his so far unexplained absence to the WWE audience.