I think there is enough historical information to make the Guaraní and Paraguayans into two separate civilizations. The Guaraní civilization could be based on the so called “Jesuit Republic of Paraguay”, a civilization built around some thirty “Reductions” or communities of Guaraní natives with Jesuitical missions. As mentioned above they could combine elements of the Jesuits and the Guaraní. They could have defensive bonuses since they fought off raids by the Portuguese (the Bandeirantes). This Guaraní-Jesuit civilization could also enjoy economic bonuses related to their cultivation and trade of yerba mate (a traditional tea). The Paraguayans on the other hand could be a militaristic civilization with offensive bonuses over economic advantages. This military orientation would be based on the strong Paraguayan army during the cataclysmic War of the Triple Alliance (also called the Paraguayan War). It took the combined forces of Brazil, Argentina and Uruguay (the Triple Alliance) to defeat Paraguay.
Here is an excellent proposal for a Guaraní civilization made in this forum a long time ago.
And here is a nice informative video about the Paraguayan War.
