I can definitely see Colombia be the anti colonization Civ.I can see gold being added as a resource if economic victory were implemented, and a hunt for gold sources in distant continents to strengthen their economy would be a good way to encourage colonization. Then, Portugal comes with some kind of colonization bonus
El dorado legend is strongly related to the Muisca people, although I find the inclusion of Muisca difficult, Colombia is considerably probable.
I've posted this on the new city-state thread and I think that if Colombia comes along a Musica trade city state can coexist and can implement an El Dorado like suzerain bonus.