Hmm. I did see, with one of the other playable races, that the neighbours info had "drows" and "drows----" when looking at the embark. Selecting the drow race as my civ, just had "drows" as the neighbours.
A) The fact they're both populated by drows means that their race-name (the last value in [NAME:drow:drows:drow]) will feature there, so if you want to differentiate them in order to pick-apart your politics more visibly, you might need to make drow outcasts a different creature entirely.
C) It doesn't generate the same level of response that a siege trigger does, but raids do work to get their attention. If you dont know what group you're sending them to because they're all labelled "Drow" you could just be raiding your own civ however.
Well, I also have an entity of "high elves" that use metals, and a couple of differently styled human entities, and on the embark screen, the neighbours would in some places show two entries for Elves, indicating both the normal elves and the modded ones would be present, same for the humans. Which only added to my confusion.
I know which one I'm sending them to, because I looked the maps up in legendsviewer, so know that X neighbouring drow civ is an outcast one, having "law-giver" and other generated positions, rather than the regular drow matriarch and priestess positions etc.
My fortress is near to sites from an outcast drow civ, so I did kind of expect to see two entries for drows in the neighbours list, but perhaps the game doesn't quite expect that kind of thing.
Oh well, we'll see how it goes.
Useful information though, about the ethics. Something to keep in mind for tuning my mod later.