Not gunna lie, literally anyone but OJ and Ethan O'Connor you can make an argument for.
Personally I like Fitzgerald in the single high safety role. But if you want him more involved I get putting him in the nickel, plus he's a great athlete.
Thornton is clearly someone who is better in run support and closer to the box. But imo out of the 3 main safeties, he's probably the worst one and the one we'd want to be rotating a bit more...
Poyser is the interesting one that probably ends up dictating things a bit though. He played Nickel at JaxSt pretty sure. But can he play the Jakobe Thomas role? If he can't then, that definitely limits options much more. Because then it means Fitz needs to either be the safety with Poyser at nickel or Poyser staying at same position as last year with Fitz down at nickel.
Damari and Antione if they want to get much more PT, should be all over trying to get into the nickel competition.
Xavier Lucas while maybe not being the every down nickel like Scott was, actually played over the slot a bit last year, and pretty sure at Wisconsin they had him doing this as well, as well as in HS him being a Safety like half the time.
Then of course there is Dunnigan who seems like is going to be the guy on defense as a freshman to get significant PT.