Most of them (thinking of Kasich, Walker, Rubio, etc. here) would have won, maybe even fairly easily. This little narrative that Trump was somehow the most "electable" Republican because of his "unique" strength in the Midwest who ran a flawless campaign is cute, but unfortunately it has always been nothing but baseless delusion on the part of hardcore Trumpists and bitter Clinton supporters.
Yeah, the only one I could see Hillary beating is Cruz, assuming things went down the same way they did in our timeline.