It is a great report! Scott painted up three packs of Foundry Swashbucklers since Sunday. In that time I have not been able to finish four single figures. I have inducted Scott into the Order of the Knights of St. Benedict Biscop. This honor will be extended to those who take pictures of a game of Gloire with painted figures.
Yes, you could do Gloire with Conquistadors and Aztecs or Incas. Eventually I hope to do a New World supplement which would spell them out fairly explicitly, but in the interim, I think you would be okay adapting the character profiles.
Certainly I'd have to work up rules for slings. Bows and spears are in there already, and those Aztec clubs with the obsidian blades should count as Long Blades.