Most likely to win character in this gauntlet?

Most feathers will go to the people who time their multipliers with their flags, not who is most likely to win. In fact, picking the losing team makes that easier as they have more multipliers and have less competition within their ranks.

That said, it's hard to say. The safest bet is Hector, but I'm not certain enough on him to say for sure.

Hector/Robin.

Well, we don't know for sure. I totally expected Lyon to lose first round in the Hero's and Villans one but he came out on top.
The gauntlet can be unpredictable but I would say Niles, Julia, and Morgan are likely charaters to lose and Hector, Robin, or Lilina to win.

You get the most feathers by picking the loser though. So pick someone bound to lose like Niles. If you just want to win I think Morgan, Lilina, and Hector are all contenders of not getting any multipliers.