I wonder if Christie, Kasich, and Fiorina will stick it out until Super Tuesday if they do very poorly in NH and SC.
You're right that Jeb will at least stick it out through Florida. As far as I'm concerned, I hope that he's in the race until the bitter end to keep Rubio from going over the top. I'd almost wish that either Trump or Cruz would drop out so that a single anti-establishment candidate could consolidate the anti-establishment vote, in the same way that Rubio will probably consolidate GOP establishment support after Super Tuesday, but that obviously won't happen. I also hope that the Trump or Cruz supporters on this site aren't representative of Trump or Cruz supporters overall with the mutual hatred of one another's candidate. I get the feeling that some Trump supporters now hate Cruz so much that they'd rather get Rubio than support Cruz, and vice-versa with many Cruz supporters. It's kind of depressing.
Christie, Fiorina and Kasich will stick around till they run out of money. But if either of these can finish a string second in New Hampshire to Trump( I predict Trump will take New Hampshire), they will be around till at least Super Tuesday. If they all do poorly in New Hampshire and South Carolina, they will be cutoff from big donors and pressure will mount for them to leave the race. Though Kasich may not formally leave till after Ohio, due to ego. If Bush manages his campaign funds well, he could stick around well beyond Florida.
I agree that Trump and Cruz need to call at least a temporary cease fire and instead focus the bulk of their attacks on Rubio. If Cruz and Trump can stop with the personal attacks and be more civilized towards each other, then there may be peace between supporters of the two and make it possible for their supporters to back the other.
No one has won the GOP nomination without finishing in the top three in Iowa and the top two in New Hampshire (nominee wins New Hampshire if they lost in Iowa). Also, no GOP nominee in open (non-incumbent), competitive elections years has won both Iowa and New Hampshire.
Trump will most assuredly win or finish 2nd in New Hampshire to keep this historical trend going. Will have to see if Cruz or Rubio can also rise from the pack to finish in the top 2 in New Hampshire alongside Trump.