Which of these Republicans could beat Hillary?

[Averroës Nix]

If a candidate is a plausible nominee within either major party, then he or she is a plausible winner in the general election, regardless of who they are up against.

Rubio, Christie, and Bush are plausible nominees. So is Daniels, but he isn't a plausible primary candidate.

Perry and Jindal are borderline cases. They have the right background, but what we've seen of them on the national stage suggests that they probably lack the right kind of political talent to win the nomination.

The rest of the names here are business plan candidates. They might run to build name recognition, sell books, and raise their speaking fees, but they lack the conventional credentials that are necessary to build support for their candidacies within the party, whether they're discredited (Palin, Bolton, or Bachmann) or amateurs (Carson or Cain).  Santorum and Huckabee have more credibility, but they're still outsiders to a much greater degree than any recent major party nominee.

[Averroës Nix]

Anyone who doesn't answer "all of them" at this point is a total hack.

The national environment in 2016 will be much more important in developing the race than the quality of the candidates, and it is extremely premature to rule any 2016 candidate out of consideration.  In a 1932 or 2008-esque environment, Hillary could get stomped by any Republican.   

Some of the Repupbicans mentioned are so unqualified and/or cooky that this seems unrealistic. A majority for Palin or Carson wont happen in any scenario.

No you're wrong.

To say that a candidate like Palin or Cain has an absolute zero percent chance of winning in 2016 would be extremely cocky. 

You don't need to know that much about how primary elections to work to understand why neither is a plausible nominee.