I'd be surprised if she didn't try to seek a second term even if she had health problems, a la FDR
Nah, I think Clinton is too much of a democratic party loyalist to do that.
IMO all these people are super, often delusionally confident, absurdly ambitious people, and Clinton is no exception. How many people other than Washington have stepped down for reasons other than they were going to lose anyways?
Maybe if it publicly leaked that she had serious health issues and it put her campaign in serious jeopardy, she'd step down and endorse someone so that the democrats wouldn't lose control.