I just read in tv guide that Jacks grandfather knows something about the island. I think Jacks dad has been there before as well.
Also says that Sawyer, Juliette, Jin and crew will meet up with a young Ben for at least 4 episodes to fill in his rise to power.
One of these sentences is true according to writers:
A: Ben is Lockes brother
B: Charlotte is the grown up Annie (bens childhood friend)
C: Miles is Marvin Candles son.
Im not sure which one to believe, but if I were to pick one, I would say Ben and Locke are brothers. A Cain and Abel type dynamic.
I think I would go with C. if I were guessing. Charlotte seems too young for B, and A doesn't seem to make sense because we supposedly know who both of Ben's parents are and neither are Locke's. Could be interesting though. I was thinking Miles was Marvin Candle's son before.