Any tips on making custom civs with custom tags

[Pirsicola Tortellini 51]

I've been experimenting on making civs in the civilization creater then adding into the game with a new tag like say dalm for Dalmatia. Every thing is working fine but some civs just don't appear at all or appear to be able to be added to scenarios but I can't have them as a formable nation or a union. I can't seamingly find a way to make a civ like this without something like this happening 9/10 so any advice would help a lot