After just posting a theory, I wanted to offer an additional theory on who Jacob was referring to when he stated that "They are coming" when Ben stabbed him.
I believe Jacob was referring to ALT Jack, Kate, Sawyer, Hurley, Sun, Sayid, and Jin and possibly Desmond: due to the list that Ben gave Michael in season 2.
The list included Hurley, Jack, Sawyer, and Kate. The list did not include, but DID involve Sayid, Sun, and Jin.
What if Ben/The Others via Michael needed to distract Hurley, Jack, Sawyer, and Kate b/c they needed to be isolated from the other versions of themselves that were ON THE ISLAND AT THE SAME TIME?
If kidnapping these four motivates Sun, Jin, and Sayid to sail towards the docks to look for their friends, then this would keep them safe (as well) from running into other versions of themselves.
(Also, in the episode Live Together, Die Alone, "Sayid plans to use black smoke as a signal, saying that "this time, they will know that WE ARE COMING", a reference to the attacks in the first season finale. ")
The only piece I think I am missing, is WHEN/WHERE other iterations of the candidates appeared on the island forcing Ben/The Others to remove them (temporarily) from the "game".
1)We saw Kate, Hurley, Jack, and Sawyer meet up when they flashed from Ajira to 1977. Sayid appeared out of nowhere (breaching the perimeter, which forced Jin and Phil to look for him).
2)We know that Locke's dead body, Ben, Sun, Lapidus (etc.) crashed WITH Ajira (sans kate, jack, hurley, and sayid) on what seems to be the runway Kate and Sawyer were helping build in season 3.
Could Desmond turning the key have caused everyone on the island in the season 2 season finale to flash TO the 1970's?
(this would answer how Kate and Sawyer were able to help make a runway for a plane that would crash 20 years later)
I have wondered this ever since we saw Jack playing catch with Tom (in Otherton) as Sayid and Kate watched from the bushes. Jack seemed WAY TOO HAPPY to be captured.
BEFORE POSTING
I have been watching LOST since day one.
This IS my type of show.
I AM NOT CRAZY, just driven there b/c I have been watching LOST since day one.
I don't take meds and/or need to get back on them..
I DON'T FLAG COMMENTS, but apparently people reading my theories do, so try to keep your need to insult me in check.
I am totally open to being called crazy, but the rules on this site ended up getting several posts removed from my earlier theory.
goldberg