Update: I also believe that I have been inadvertently locked out of finishing the Ara Kei questline (when I was fighting them and made this post, I hadn't realized you had to choose diplomacy. I reverted to a prior save, post doing diplomacy with my first quadomme, but pre fighting the other two.)
When I found the first dominatrix and lured someone to them, after the "win" screen (with loot and combat finish) I immediately had an encounter with the same quadomme, given the options "Yes", "No", "Fight It" and "Diplomacy", but I figured it was a glitch and just pressed "No" to back out. Now that I have tried diplomacy with all three, I can't get the fourth quadomme encounter to pop up, despite it being marked as a star on my map. Unfortunately, I did that a bit ago and have saved over it since, so I'll try to cheat and force that forth encounter later if I remember (any advice on how to do that would be appreciated) and I don't have a save profile to demonstrate- just a new one, showing in my log that I have 3 quadomme's done and the fourth unable to be talked to (unless this is also user error, which is completely possible.)