One thing they may have explained but I've missed.
Michael and Walt? What happened to them?
They got out, via a boat, provided by Ben.
Walt (and potentially Aaron, Claire's son) were considered "special" because they were candidates to be the Island's protector. And as Walt had a rather special gift (as did Hurley and some of the other candidates), he would have made a particularly nasty protector.
So Smokey (who Ben thought was Jacob) and Ben worked to get Walt (and Michael) OFF the island...while also eliminating some of the other candidates (though Libby, I guess, was accidental). I guess even Smokey found killing a kid distasteful (or, maybe, impossible?? No "stain of sin" on them?).
Walt was left with his grandmother because Michael came back sort of "damaged"...as in, a bit loony...after the events that took place. Tom (likely at the behest of Ben/Smokey) shows up and offers Michael a chance at "redemtion"..which, really, is a Ben/Smokey Ploy to outwit Widmore and kill some more candidates. But Michael falls for it, and heads out to join Widmore's expedition.
He ends up dying on that boat saving some of the other "big name" characters from the bomb...thus "redeeming" himself, to some extent, from his murder of Libby and Anna Lucia. But that wasn't Smokey/Ben's plan....just a "happy accident".
His ghost shows up in the last season, to give Hurley some advice (and to apologize for killing Libby). He reveals that, though he found "redemption", he's still stuck on the island, unable to pass on to the afterlife, because of the things he did on the island. So, it sounds like the "redemption" he was looking for, he never REALLY got. Guess that's what comes from working as an agent of Smokey and Ben.
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