None of the 2016 candidates will be the nominee in 2024. Among other things, Trump's win and the rise of the Tea Party show that Republicans really, really prefer fresh "outsider" candidates that speak to them on whatever Fox News is talking about that day than those who have been around for a while and can be called career politicians.
Also the political careers of most of these guys have been over for several years (Jeb, Walker, Jindal, Santorum, Christie, Huckabee, Fiorina, and of course Jim Gilmore)
Trump's 2016 run was his second run. The first time he ran as a reform party candidate in 2000. There's also been talk about him running since the 1980s. I wouldn't call Trump fresh face.
Was he a fresh face in media? Of course not. Was he a fresh face in Republican politics? Absolutely.
Both of those "runs" were brief and for independent candidacies. Also they were mostly for media effect. Coupled with the fact that he was a hardliner on immigration when no serious GOP candidate really was, he was definitely fresh in the eyes of conservative Republicans.