Ah. SE3 was like that. There was no relation between empire name, priority of weapons research (SE3 had no moddable AI, so you just picked 2 weapons areas for the AI to research and use), and shipset/images. It was annoying.
You could go to a site such as
Monolith's and get a bunch of race pictures. Create some flags. Have your program create a bunch of random neutrals using these images.