So I'm doing the Repconn quest Come Fly With Me, and I'm at the part where I have to kill all the Nightkin in the basemant. I definitely killed every Nightkin, but it's saying I haven't.
So I looked up a guide, and they all recommend heading to the Nightkin Antler near the start and convincing the Nightkin to leave on their own, but you can't do this if you've killed any. Thing is, even without knowing about this, I encountered hostile Nightkin in the hallway leading up to him anyway, making that option impossible. They wouldn't normally be there, so I'm thinking one of my mods, like IWS, increased the number of Nightkin down here, and I think that may have broken the quest somehow.
Any advice? Maybe there's one in some weirdly obscure area? None of the guides I've found actually say where they all are, because they all recommend just convincing them to leave.
I've killed at least 3-4 wandering the hallways, plus Antler and the Jailor.

maybe you have to kill the ngihtkin jailer?

I already have. I've also done the Harland thing and found his dead friend for him, and gone into the section where you see the giant nukes being horded, and spoke through the intercom about it.
-Edit- I decided to just go back to an old save and carefully sneak by with a Stealthboy, so I was able to finish it.