I think Jon, Stannis, and Sandor will all be back. Stannis and Sandor simply because they didn't show them die on screen. We all know this show has no problem with gory content, so if they're really dead... Why not show it? Jon will be back cuz they can't lose such a big player like that. I know they've killed big players before, but none from THE trio of Tyrion, Dany, and Jon (Arya's rising too). With the Red Priestess back in Castle Black, that seems the most likely route. If not her, I'm sure something else will come up later where Jon comes back.