Even though it would appear that Jin died in the sub, and I'll admit we're all pretty sure he's dead, according to the rules of the show and according to what we've seen and know, Jin MUST be alive. Here's why:
First of all, Jacob said to Kate that he crossed her name out because she became a mother. Even though Jacob also said she could still be the candidate, that didn't stop him from crossing here off the list.
Hence, we must therefore assume that Sun's name, (had she been a candidate), would have also been crossed off. But, since the Kwon name WASN'T crossed off, we MUST assume that the Kwon who was a candidate was Jin.
Now, technically, (according to Flocke's plan), Sun was killed by Sawyer on the sub. But Jin was NOT killed by Sawyer, but rather he chose to die with Sun. (i.e. kill himself)
But, since by my earlier logic we know that Jin is the Kwon who is a candidate, we know that he CAN'T kill himself.
Because of these things that are true according to the rules of the show, Jin MUST be alive.
Please feel free to bazooka holes in my logic.