I'm still sceptical about the whole Zulu/Kongo thing. Don't get me wrong, conquering the world as Kongo would be a great way to annoy the Americans (no offence intended for Americans reading). I want to see those civs. I'm just not sure it's going to happen.
Re Nzinga, it's most likely that if Kongo was confirmed, she'd still lead it, and Firaxis would bend the rules a bit (like giving Napoleon that trait which referenced the very system which he destroyed). The truth is that there aren't that many viable female leaders. I'm not trying to be sexist, I'm just saying that ancient civilisations generally were.
As for Zulu, South Africa's colonisation was chronologically set apart from the rest of the "Scramble for Africa", plus they're on the edge of the continent. Scenario wise, Kongo makes more sense. It's most likely that we'll end up with Shaka or Dingaan (sp.?) if Zulu gets in.
Don't get me wrong, I want to see Zulu and Kongo in. I just don't think it's a certainty.
As for the Garamantes, again, it's not going to happen. I like Tomatekh's rendition of them, and their water-finding prowess would lead to a civ which makes desert worth it without Petra, but their empire is too small. If I had my way, the dark horse would be Ryukyu, but that's even less likely than Garamantes.