Depending on the matchup, Gonzaga looks like an easy pick to lose in the first round. Good efficiency numbers and such, but unless a team is stupid enough to hack them the whole game they're in trouble. It's an automatic red flag if a team relies heavily on free throws because of how much it varies crew-to-crew and because some teams don't have to foul as much as others do.
And in terms of teams seeded 12th/13th or lower that could/will pull an upset, I'd pick either VCU or Belmont.