Any 2h weapon should be able to "Cleave" because you are just swinging the weapon in a big arc in front of you, it doesn't matter if it is a sword/spear/staff or club if it is 2h it gets access to "Cleave"(maybe rename this?).
I doubt this. The weapon should be really sharp in order to be able to cleave through mutliple bodies. With a blunt weapon perhaps a kind of domino effect could be accomplished, but the adversaries should stand in a straight line for that, not an arc.