I think the namelists are all in the localization files, which you can directly edit without using the SDK. However, if Firaxis pushes any updates, your localization file changes may get overwritten. There are entries for them, but editing them does nothing when I try to generate a random character from either the create function in the pool or having them just as appear at random, even when starting a new game. I've been trying control tests where I whittle down every nationality and gender to one first and one last name as possibilities but I still get the full array of names regardless when characters are generated.
