Well yes i know the Aztecs, Mayans and Incas were Native American. I meant Native North American when i said Iroquois and Sioux. BTW when talking to me, note that i consider Aztecs and Mayans as Meso American, Iroqious and the like as Native American, and Inca's as well... i don't really call the inca's anything...
Brazil, Mexico or Brazil? I thin you meant Venezuela, but, i'll give it a shot.
Mexico - i guess you could call them an important player in the history of the America's. There isn't really a reason other then to just have them.
Brazil - i think it's pretty obvious, big important country.
Venezuela - Very important in the history of the Americas. Have you ever heard of Gran Colombia? Simon Boliver? Liberatadors? i say Venezuela/Gran Colombia's war of independence (which includes Colombia, Panama, Guyana, Surinam, Ecuador and Peru as well as Venezuela) is much more interesting then the american war of independence.
As for the Swahili, since your so interested in Southern Asian civilization, you should know about the Swahili, who have traded alot with Arabia, India, and later on Europe, And got rich doing so. Sure they were never a unified state, But instead they were city states like Greece or the Maya.