Hank is going to survive because it wouldn't be enough of a tragedy if he died now (also, that phone call was way too much of a cliche final phone call not to be a red herring). As far as I can remember, every major character to die (or even to get seriously hurt) was killed as the result of their own choices, usually…

well, if there's infinite possible universes, then it doesn't matter how improbable it is, because it's still possible which means there must be a universe where it exists. 

OK, I think I've figured out the ultimate explanation for everything that any of you have brought up:
After the old man bought Curtis' power, he realized it wasn't good enough to kill Hitler and so he used it to go back to the instant before buying Curtis' power and ask the power dealer if he had any better time travel…

I think the confusion comes from the season 2 finale when the dealer clearly tells Curtis that he sold his power to some old guy who wants to go back and kill Hitler.

Just had a sad thought:

But when he changed things so that all the other misfits ended up dead, he didn't realize that they were dead in this timeline until Nathan told him. I think he was basically able to hold the same versions of reality in his head as what was shown to us, but whenever he flashed forward he didn't know what he had missed.

So, has Kelly now been replaced by alternate-universe-Kelly? She clearly remembers things from the alternate timeline, but does that mean that she won't remember any of the events from the 'real' timeline? When Curtis changed the past, I think he was only able to remember things from his original timeline, not the new…