I think it is more likely, seeing as one physical body can't enter the spirit world unless the spirit portals are used. And considering they wouldn't be opened for another 71 years, it is the only real option left.
Yeah sorry.I think I posted that before I saw legend of Korra since I hardly knew when it'd be on.Or I simply just forgot because I hate the twisted sunovadouche and i wanted him torn apart to millions of pieces.
Well, I actually wrote a fanfic that serves as an alternate sequel to ATLA which retcons his fate and the graphic novels. I wrote it before ATLOK Book 2 began airing, so after Book 2 finished my theory of him surviving has been rendered moot.