Yes its true monks are strong against anything weak to Bludgeoning or Bashing Damage. This includes Skeletons as well as Magic Pots. In this BCNM each ghost has a weakness. Murdock seems to be weak to Bashing Damage. So thats why 2 mnks has been suggested.
I haven't tried this yet but we were planning on doing this with PLD equipping Earth Staff, MNK/WAR and RDM/WHM. Hope this works :O