The modding guide is only current to Legends, not Shadows. In the section on Characters it states that the text file uses the following numbers to determine a character's role:
The type of character, selected from one of the following values: 1=Faction Leader, 2=Ambassador, 3=Colony Governor, 4=Fleet Admiral, 5=Troop General, 6=Intelligence Agent, 7=Scientist
Today I wanted to mod a different role, one new to Shadows. The role of Pirate Leader. I experimented by using the number '8' under role in the modded text file for humans, and sure enough it corresponds to characters with the role of Pirate Leader.
So a revised modding guide should read:
The type of character, selected from one of the following values: 1=Faction Leader, 2=Ambassador, 3=Colony Governor, 4=Fleet Admiral, 5=Troop General, 6=Intelligence Agent, 7=Scientist, 8=Pirate Leader
Apologies if this has already been discovered.