Alright, so I assume the party knows to try and be fast. It says that the boss could fail a save against a 'magic locket'& what's that about?

Meanwhile first round seems obvious enough- barbarian comes up and shoves the armor away from the door, then opens it. Gets attack by the armor, then cleric comes around and Readies to Silence the room. The thug knocks on the barbarian, then the druid fills the room with Conjure Animals and orders them to kill the BBEG, then cleric Silences. Warlock Dispels the Armor. I have no idea what the paladin will do yet.

The witches can't do **** and the BBEG by the time she can do something will be forced to engage the animals (and can't order them, assuming animals survive an attack from it).

This is just a rough draft while I wait for the reply, but I think that's a pretty sweet position to be in.