I know I am going to get alot of hate mail on this, and beleive me, I don't like the idea either.
But what if Zoe's last name is Wallace? And she is the mystery candidate?
Personally I think it is Kate who is one of the 6, but look at some facts about Zoe:
1. We don't know her last name.
2. Hurley was asked to set the wheel in the lighthouse to 108, so They could find the Island. Presumably that meant the sub, and she was on the sub. ( I know this could mean Whitmore or Desmond, God help us if it any of the other bozo's from the sub.)
3. When we first see her, She tells Sawyer, "I m the only one left, everyone else has died." Foreshadowing?
4. Clearly she knows alot about the Island. She is looking for all the em pockets on the map and asking Jin for some help finding them. Then Flocke says to Desmond, after describing the em energy characteristics of the well, "Afterall this is not the only well." I took that to mean there are other such EM sources around the world, ike Eloise told us in Season 5.
I think there may be an off chance, anyone else think she may be Wallace?