I've found the xml. files with the Campaigns_FTGU.xml and the Campaigns_Known_Galaxy_Large. In FTGU, the locations are listed but in the Known Galaxy, the code simply says "Locations: Known_Galaxy_Large"

If I was to swap that out, would that just break the coding?

There's another one that is 'Full_Map' which has all of the locations but I worry that might too just break the entire game

Okay, I found a solution to this. I learned that the CIS/Hutts/Republic all play with different planets (with some overlap) so I got them into a single doc, eliminated duplicates from both the planet and trade routes, and then pasted it back into the FTGU folder. Seems to have worked. There are a few trade routes (planet links) that don't work but I can't find them and it just says config error so I'm not too worried overall