Further name related questions:
The raws contain word tables, and I suspect each table is used for the naming of a specific category of things (I didn't find a single region in my world with either a Front or Rear Compound, for instance, while rivers used a wider range of names). Has anyone figured out which table is used for what (The tables I had at indices 35 and 37 seem to match the one used to name a fortress or a group on embark (both seem to use the same set), for instance)?
It also seems the parts sub structure is a reordering of the items found in the fortress naming UI:
0: Front Compound
1: Rear Compound
2: The X
3: First Adjective AND Second Adjective (both seem to use the same table, which makes sense)
4: Hyphen Compound
5: Of Y
Edit: Ignore the question above as the assumption was incorrect. Annoyingly, the only two tables that contain composition of the names of all regions are the same as the ones matching rivers and fortress/group name generation, i.e. tables 35 and 37. Thus, the rules for how to create region and river names are somewhere else. This, of course, assumes my my matching attempt isn't flawed.
Edit 2: Maybe the initial assumption wasn't flawed, after all. I get more matches with the tables at index 1 (rather than 0).
Edit 3: No, the matching tables are far too large to be useful for restricting name generation to what DF produces, most of the seem to be the same as the fortress/group one.