As much as I hate to admit it, what we're seeing with the city-states is pointing to Italy. I'm hoping that it'll at least just be Venice, which was a much more important faction at the height of its power than unified Italy ever was. Glass could be the secret resource.
We still need another North American Native civ to go with the CW scenario. I don't know nearly as much about native culture as I probably should, but the Sioux are oft-requested and I think the Cherokee are another viable choice.
This leaves one spot vacant. I'm going with either Indonesia or Vietnam here; Vietnam gets the edge because they could put the ideology game on display whereas Indonesia's main focus (trade) is already taken up by Portugal and possibly Morocco.
So... In short, final guess is Venice, Sioux, Vietnam.