In this saboteurs quest the best way to find out what an elite armour of some faction is to chech it out in troop editor. Just check out how an elite unit is equipped (Boyarin for Rus, Moznowladca for Poland and so on).
But I have another problem with this quest. I have an armour and released all my units and companions (I formed these small groups of them). But I have 4 lords in captivity and don't have any castle on my own. I don't know how to release them or give them to smb ( I have to because boyarins don't want to go with me).
I will be very grateful for any recommendations