We actually do have a Mastermind in game, but they aren't Mojoman.
Instead, they're actually iLTS.
My reasoning is also based on the two abilities I know he has, for starters he has his own personal masonry, which he basically fell silent in and didn't actually help me with Scum hunting at all after Mojoman was caught, so I suspect he's scum who wanted a Town players viewpoint to help him discover who Scum was. That entire day 1 gambit was to find a Town player to contact.
And the other ability is the one we've all seen, the perfect tool for forcing a lynch against Mafia so they would be eliminated.
Also, I'm still stating K_Y or Retaliation is the other Mafia member.