The Don is the last Mafian we don't have anything on, since we know the Spy is either Drizzy or Melody and that can just be figured out at the very end of the game.
This list has provided us with a pretty good opportunity though. One of the FIRST THREE PEOPLE on this list is Mafia. We kill one at random NOW, and the next round the Detective will investigate one of the remaining two, unless we were lucky enough to get him on the first try. If the one investigated is the Don, they're marked for death. If they're not, the other person is the Don and is marked for death.
I vote Frank.