[Endoperez]

I did the same back in Dom2.

You don't have to adjust these:
1. Flags. As long as you can see what name corresponds to what flag, it shouldn't be too confusing.
2. National descriptions: already available, since the original nation also plays.

Nation-spesific pretenders and spells will be the most troublesome. There's no easy way to do pretenders. You have to copy each pretender choice and restrict it to the copied nation number. Same for national spells, but since you don't have to define a number for spells you don't have to make three different versions if there are four identical nations battling it out.