String Theory - It Just Don't Add Up!

OK, sorry to be the annoying fangirl here, but...tonight's episode has so many logic holes it made my head hurt. "Take That, Causality!"
1. Why didn't Matt "reads minds" Parkman realize the president was Sylar instead of Nathan?
2. Why didn't Haitian "reads memories" superguy realize the president was Sylar instead of Nathan? and why didn't the Haitian's neutralizing powers reveal Nathan as Sylar?
3. If Claire was never killed by Sylar, why did he regenerate when Hiro stabbed him in the alternate future universe? Also, Claire never died, so why did Hiro think she did?
4. WTF?

In future, my dear writers, don't pick up time loops that you're not powerful enough to handle.

In other news, I went to a reading by Peter S. Beagle, author of The Last Unicorn, and many other cool things. It turns out he's a Buffy fan! Who'd a thunk it? And his favorite actor from the show was Spike. And that his father told the story that appeared in BTVS - the one where Dawn brings her mother back from the dead with demon power - which was apparently ripped off from a famous sci-fi author. Ha! Anyway, Peter S. Beagle was super cool, and now I have a signed copy of the alternate version of The Last Unicorn signed to my little brother, who is also a huge P. S. Beagle fan.

PS For my birthday, couldn't they have done an alternate universe that made more sense?
PSS I'm excited about the little girl who apparently has the power to take down Sylar. But, since he wasn't the exploding man after all (as Peter explained in anti-logic alternate future universe) - maybe it doesn't matter?