It seems both the cave scratchings and the names on the dial in the Lighthouse are both Jacob's candidates. Do you think we'll later learn that one of them belongs to Smokey? Or is it that Jacob is gone and smokey isn't so he doesn't need anyone to take over for him? Or perhaps, it's not even possible for someone else to become Smokey since it's more of a monster rather than a man.
Maybe the cave is the list of MIB's candidates and the Lighthouse (dark and light contrast again) is Jacob's -- which could explain why some of the numbers and names are slightly different in the two places -- but, at least going off of right now, why do you think Jacob seems to be the only one in need of candidates?