I'll keep this short and to the point.
In Ab Aeterno, we see the end of the conversation between Llana and Jacob. Jacob asks if she would help Jacob, and she agrees. Jacob goes on to tell her there are six people she needs to protect. Obviously he is refering to the candidates.
This gave us a big piece of information, there are ONLY six remaining candidates. Here they are (or so i thought):
1. Jack
2. Hurley
3. Sayid
4. Sawyer
5. Jin OR Sun
6. Locke
But theres another. During the episode Lighthouse, if you look on the wheel in the lighthouse closely, you will see a seventh name. The name is Austen, and it corresponds with the number 51. Austen refers to kate, and the name was not crossed out.
I think that when Jacob said that there were six people that Llana needed to protect, he allready knew that Locke would not be one of them. In other words, the six remaining candidates are:
1. Jack
2. Hurley
3. Sawyer
4. Sayid
5. Jin OR Sun
6. Kate
Kate is the last possible candidate. It is highly inprobable that she is the replacement, but now we can be assured she still has a huge part left in the show.
Please comment.