This is oversimplifying it but I think you'll get where I am going. My theory is that the numbers on the compass and the corresponding names are just coordinates. In other words, if Jacob wants to "look in" on Jack then the wheel needs to be set to number 23. Most of the names listed that we're familiar with are people who have played a role in the story. If you look back at LOST over time, there have been a lot of instances where one person knew things about another that they should have never known. For instance, when Mikhail knew all about Locke, Sayid, and Kate. Or when Juliet and Ben knew all that info about Jack when he was being held at the Hydra station. The compass at the lighthouse and the list in the cave may simply explain how that happens. You dial up the person you want to "watch" and there they are. It's unrealistic to think that every person on that Island has been a candidate. A few of them are but I believe the rest of the name/number correlation is simply a place marker or a "scorecard" for lack of a better term. I really don't believe that every name listed has been a "candidate." Think about it, Karl? Friendly? Some of the names were such bit players that it's hard to imagine they had any relevance to anything.
As far as the cave vs the lighthouse the symbolism is obvious. In short, un-Locke has the cave. He's "evil" so he's going to be "underground" or "below" like Hell. Jacob is "good" so he's in the lighthouse. He's "up" he's in a spot where he can observe from above. The names and numbers are simply a scorecard to keep track of the players.
The real question is what game are we playing?
I like your post, but I don't think it is unrealistic to assume everyone on the island was at one point a candidate. Why? There's been a theory since the beginning of the show that everyone on Oceanic 815 was chosen and guided to the island. I think that this theory has been pretty well proven for some of the characters. I would venture that no one comes to the island without Jacob knowing about it, and few people come to the island without Jacob allowing them to. Keamy may have been one of those few, but we all know what happened to him and his men. Bram and company may have been others that Jacob didn't want, and they got Smokey-fied. I think it is perfectly realistic to assume everyone's name on the Lighthouse and in the cave are Candidates.
Based on that logic you're ready to say that Frogurt, Nikki and Paolo, Artz, the hypochondriac from the golf course in Season One(I forget his name), and a host of others were all candidates?
Not that I'm disagreeing or questioning your logic but; care to state your case for why Frogurt or Nikki and Paolo were in line to take over for Jacob?
I'm with you on that being the case for "some" of the characters; but I just can't get onboard with the idea that everyone on the lists in the cave and the lighthouse are candidates. All along it's been about getting Jack where he needs to be. If the "game" is a chess board then Jack is the King. Everyone else is playing a role but this whole "game" thing has been about Jack since day one. He's the one and only "candidate."
Un-Locke, while seemingly honest, is clearly the bad guy here. He may seem to be telling more "truth" than Jacob is right now but in reality, un-Locke isn't lying, he's simply omitting key facts as he "recruits." Up to this point we haven't seen Jacob play it straight with anyone. He's the good guy but honesty and being forthright isn't his strong suit. This whole idea of "candidates" is simply a diversionary tactic. Why is anyone's guess at this point but I think as things play out we'll see that there is not and never has been a list of "candidates." Jacob can easily manipulate what happens and he seems to know what's going to happen before it does etc. With that sort of ability, are we really supposed to believe that he has no idea who he wants to "replace" him? If that's even what he's looking for?
I've said it's been all about Jack since season one. I'm sticking with that until the show proves me wrong.
