Is it possible to use a BA/Kalmar faction for a unique custom settlement?

[Undead Martyr]

My understanding is that a unique faction variant of e.g., a huge city is tied to the faction creator on the strat map. Which begs the question- if one uses a BA shadow faction, and sets that faction as the creator in descr_strat, can one then use that "slot" for a custom settlement map?

[Callistonian]

Yes. You can use any existing faction as the creator in descr_strat and in the world package file.