I think the cave of names has more significance than just being possible candidates. If you think back to the opening of The Incident, Part 1 Jacob and MIB are talking as a boat appears in the background. The assumption, we the audience, is left to make, is that this is the Black Rock.
Anagrams have been common through the series, but I am repetitively drawn to Rainer Canton = reincarnation.
I think the names in the cave are people, like Jacob and MIB that were on the island at one time, but managed to get away/escape/turn the FDW or whatever and live elsewhere. Their spirit is linked to the island, and so they are drawn back, like a moth to the flame; either directly or by the hand of Jacob.
So we have this "roster" of names, and it is hidden within the belly of the Island, which I think is also significant. Our identity is etched upon our soul, and so too are these names etched upon the inside of the Island.
What do the numbers mean? I first thought the numbers were somehow connected to how many times they came to the Island but that doesn't seem right. Perhaps it is guide to connectivity amongst the group, i.e. Locke - 4 would mean that a member of the Locke family line would have 4 connections to other people on the Island, Shepard would have 23 connections, etc. But looking at the list, there are 'unknown' characters that have high numbers like 346/396 associated with them, so someone we have yet to meet can't have that many connections. Also, for one person to have a large number of connections, everyone else would need to be connected to him/her, so the distribution of numbers doesn't work out with the amount of large numbers listed. Perhaps the numbers are just numbers. Perhaps they are seat numbers, as Jack was 23 on the plane and the list, for some other vessel...
Sorry for repeating anything said by another, there are many many theories here, I haven't read them all...