So Jin, is the reason that Russeo and by default Alex is alive, since it seems to be that the rest of the team went down into the temple and got the "sickness". The killing of Alex also set Ben off to do things not yet seen, because of this prior action.
It also seems to me that Locke made himself the Leader of the other's by telling Albert to check him out in the hospital when he was born.
And Daniel, who says the past can't be changed sure seems to be trying. He tries to get Desmond to help as well as, tries to tell young Charlotte not to come back to island. And he is for some reason at the orchid when it's being built.
Things that make you go hmm...
I think they are telling us this story now pulp fictions style and if we can put the pieces together in chronological order, we will start to see how things are coming together.