One possible issue is choosing the language, as the Mississippian cultural sphere encompassed multiple ethnic groups. Would it be Dhegihan Siouan of the Osage spoken in Cahokia, Muskogean of Coosa, Caddoan like the Wichita of Quivira? Cherokee because they are the most numerous today and have an even greater number of white people claiming descent from “Cherokee princesses”, making them an obvious choice from the marketing point of view, even though they were vassals of the Muskogee/Creek-ruled Coosa? A mix of various languages?
Making a civ out of every chiefdom encountered by De Soto might be a step too far, but one civ for the entire Southeast wouldn’t be ideal either given the utter lack of known leader names.
Assuming Devs are generous and we get a five civ DLC again, I’d go with the following to cover the five major language families prominent in the east:
- Siouans (both the Dhegiha of Cahokia and the Sioux of the Seven Council Fires up north)
- Muskogeans (a fairly straightforward umbrella, unlike other ethno-linguistic groups they inhabited a continuous territory and were eventually united as the Creek Confederacy.)
- Caddoans (Quivira, Caddoan Mississippian Culture and their descendants like Wichita, Pawnee, etc.)
- Iroquoians (Haudenosaunee Confederacy, Monongahela culture, St Lawrence Iroquois; I’d risk adding Cherokee as well, despite the cultural differences they do have oral history of migrating from the north and Ghigau can be a cool UU. And including them enlarges the pool of AI leader names.)
- Algonquians (basically an umbrella for everything Algonquian. It’s debated whether Shawnee belonged to Fort Ancient culture or occupied mounds erected by previous inhabitants, but they are prominent enough to warrant inclusion. The Mississippi river and Cahokia are now known under their Algonquian names after all. Plus Vinlandsaga needs its Skraelings.)