So I'm happy with vaulters being valters, and disabled Mezari in my mods. 


Playing a 3 player multiplayer game we could not choose Mezari - However with Shadows, Shifters and Tempest disabled we played with 5 random non-duplicating AI. We din't have a cultist faction, but did have Vaulters and Mezari turn up.


Thought I sould point it out!