I've never played in a 2 QB league, and with 12 teams...
If it were me, I would keep OBJ and D Thomas. Reason being is that QB's don't usually go early in a 1 QB league because the position is so versatile. You could start Blake Bortles and RG3 and still have a decent team. If you kept D Thomas and OBJ, your WR core would be untouchable, especially in a PPR league.