I would have said torque/engine/trans mounts first when you mentioned the vibration. Belts/A/C compressor is another.
I don't think it is the PTU/RDU due to the fact that it goes away when the car is in motion. The driveshaft tho, is a possibility, because it is disengaged in P and N, but engaged in all other modes. If the vibration is in the floorboard, that is a good indicator.