I would disagree with your choice of Inuit as the representative civilization for SA/NW North America. Before their culture was significantly changed by the Europeans, they were nomadic, and though they manage to thrive - amazingly - in arctic conditions, there isn't much that they would add to Civ in terms of actual civilization (the building of monuments, long-lasting settlements, culture, law, art, religion, warfare.) I'm not saying they don't have any of these things, I'm saying that they are not what I would consider a 'civilization' for the purposes of this game.
Instead, I suggest using the Haida or perhaps one of the Salish peoples (or just use 'Salish'). The Haida in particular built long-lasting settlements, created very beautiful artwork, traded and fought along the coast for hundreds of miles, and had a culture that could be more accurately called a civilization in the way Westerners use that word today. These people were able to devote far more resources to nonessential things - like art - than were the Inuit, and at its heart, I think, civilization is the ability to create things that are nonessential for survival of the individual or group.
EDIT: Oh, wow, this is a poll. Well, I vote Other North American Native civs - Haida.