Balerion the Cat

I think (pure speculation, no evidence) that in the end the difference between who can have a chance to survive to the Others and who becomes a wight will be made by the protection of the Old Gods... The brothers who made their vow near the Weirwoods will be protected more, in some way (and before the end this will maybe prove useful for both Jon and Sam). So, if I'd to bet I still think CH is Benjen, who managed to survive in some way (and not completely living, see the cold and black hands) after an encounter with the others, protected by the same magic which opens the Black Gate (sensitive to the NW vow).