What about Guarda do Vice-Re (sorry for any Portuguese-butchering!) / Viceroy’s Guard as alternative name?
Seems a lot of Portuguese colonial/frontier areas made use of Dragoons, with Brazil being the most prominent. Dragoons (and other military) were specifically sent over to Brazil in the 18th century to protect the Viceroy, clash with the Spanish at the frontiers as well as guard the valuables (gold, diamonds, etc). Their post-rev successor are already in the game (Independence Dragoons), but there’s room for both.

