I think that settles everything, then.
Jack and Hurley are on one side. Jacob easily convinced Hurley to return to the Island. He also convinced Jack, but he's having a hard time convincing him of his supposed duty now he's back. But I doubt Jack will continue to resist. He ended up pressing the button every 108 minutes after Desmond left. He ended up being a believer in destiny after Locke's death. He will end up taking on whatever Jacob wants him to do.
Everybody else outside the Island is on the other side, or at least, will be on the other side. Flocke already convinced Sawyer last week. Kate, because her heart flutters a lot, will go with him. Jin will be a wild card, because he'll actually bring Claire--a threat, according to some definitions--to the Temple, thanks to his stupid lie about the Others holding Aaron.
It sucks to say this, because I didn't expect to make a prediction on how this will all look like towards the end. Here goes anyway: the final showdown is going to be Jack versus Locke. Again.
Apart from Jack and Hurley, whose roles seem to be pretty much defined, everybody else will end up as collateral damage. Perhaps Flocke will have the other candidates fight, exploiting the loophole once again. In the end, it's going to be a showdown between Flocke and Jack, much like the Joker facing Batman. (I didn't want to compare Hurley to Robin, but wasn't that obvious?) On Jack's side: that other person who's returning to the Island.
Is it you, Desmond?
It does seem that he is capable of subverting whatever it is that needs subverting. The rules don't apply to him--we've long explained that--and his surprise appearance on the alternate Oceanic 815 seems to suggest that. Of course, there's also his many adventures involving Lost
's idea of time travel, and you have the perfect weapon against the Man in Black and his attempts to, perhaps, take over the Island and do things with it. I'm betting Hurley's travel-to-the-time-of-the-dinosaurs comment earlier was a slight hint to what happens next...
But what if it wasn't Desmond? Widmore, perhaps? Apart from knowing the intricacies of the Island like the back of his hand, he also gave us Daniel Faraday, he who dissected every one of the Island's time travel follies before he fell victim to it. Or maybe not. The Easter eggs from the episode reveal that the piano piece young Daniel was playing is the same piano piece David, Jack's parallel timeline son, was playing. That could confirm Jack's bigger role on the Island. What if David is Daniel's second coming? Everything repeats in the other timeline--provided things get fixed in the actual one. We'll see.
(Image courtesy of ABC)