I would also prefer Dante, buuuut I feel Nero would be slightly easier to translate due to having a bit more of a simplified moveset. Though I guess what other tricks he has would depend if he's based on DMC4 or DMC5 Nero. Either way, if Nero has Buster/Snatch/Charge Shot/Streak he'd be fun.
If a DMC character were added, would the delay inputs get you different combos, or would it be better to set them as combos for Side-Tilt/Down-Tilt ect.
With Dante, I would probably keep his moveset to Rebellion+Gloves Boots (be it Ifrit/Beowulf/Gilgamesh/Balrog) Since the latter style of weapon has almost consistently been with Dante in each entry of the series. If possible, of course adding in Ebony/Ivory and Coyote A as they are also staple weapons. Though they'd probably have to look more "lasery/fantastical".