I am betting whoever the person is, it will be a short, very short visit, which is why I am no longer guessing. Too drawn out now, for me. but that is just me.
Days has made too big a deal out of some returns of late, which were just disappointing. I had so looked forward to Jack's return, 5 episodes, etc. I think that the show decided to put all the Jen/Jack stuff into one episode instead. Yes, it was a good episode, very good, with outstanding work by the two principals, and everyone else involved. But there has been NO explanation of what happened to the FIVE shows. i mean, they could have just said something if there were to be more, or that they decided to combine it all.
So....no longer any interest in who might be coming back, as I feel, whoever it is, the hoopla won't live up to what we see on screen.