If you look around, you’ll see some profiles of the potential nominees (kinda) advocating for that person. Here are some examples of profiles of some of the more moderate candidates: Bloomberg profiled Joan Larsen; Allison Eid profiled here. Given the emphasis of the presumptive President-Elect on media, it seems plausible if not downright likely that the nominee will be the person that will generate the most attention on TV. Perhaps that means if none of these potential candidates generate enough media excitement (and yes that includes intense controversy) then we might not see any of them nominated. (Former?) #NeverTrump-er Don Willett (profiled here) might be the best bet because he is already an internet star (in legal circles anyway).
For all we know today, the presumptive President-Elect is trolling Dems (and maybe some Rs) to learn which of the people on the shortlist is most offensive, and therefore generates the most controversy and media attention.