The Congo could work.
Leader: Chibinda Ilunga, or Nzinga Nkuwa if you want a more realistic leader. Changes to Mobuto or Kabila at respawn(ideally 1950-1970)
UU: Fidalgo(from CivGold) or Adze Warrior(from my Luba Civilization, Axeman with 2 first strikes)
UB: Mbudye Council(From my Luba Civilization, Library with +1
)
Spawn Time: 1300AD(Early, but it's to give them a fighting chance)
UP: Palace gives strategic resources(I need a name for this)(not the end-game ones), alternatively, let them clear jungles pre-biology.
UHV1: Possess six cities by 1500AD.
UHV2: Build four Mbudye Councils by 1600.
UHV3: Lose no cities to European nations by 1900.
Core: All of present day Congo and everything that falls within the Kingdom of Kongo.
Stable Area: Core, plus South Africa, Madagascar, and the Seychelles.
Other things: The Netherlands could get a conquerors event at 1870 to represent the Congo Free State. I know, Dutch=/=Belgian, but it's the closest we've got.
Names:
Kongo Peoples(no cities)
Kingdom of Kongo(6>X cities)
Kongo Empire(X>6 Cities)
Democratic Republic of the Congo(Democratic)
People's Republic of the Congo(Communist)
Republic of Zaire(Totalitarian)(The name when Mobutu was in charge)
Caliphate of Kongo or Islamic Kingdom of Kongo(Islamic)
Islamic Republic of the Congo(Islamic Democracy)
Satrapy of Kongo(Persian vassal)
Province of Congo(Roman vassal)
Sultanate of Kongo(Arabian vassal)
Spanish Congo
French Equatorial Africa
British Congo
German Congo
Soviet Republic of Congo(Russian Vassal)
Khanate of Congo(Mongol Vassal)
Eyalet of Kongo(Turkish Vassal)
Tributary Kongo State(East Asian Vassal)
Protectorate of Kongo
Yes, the Congo didn't do much, but really, neither did the Aztecs, and I believe it's much better than leaving Central Africa dry.