Oh! Now I see what you meant with defensive bonuses! Allright, the Dragoes are fine that way, sorry for my ignorance
I'll give some ideas for UBs
Casa de Fundição: +2 gold per population in this city, replaces market or bank
Latifundio: +1 food from farms in this city, 40% food is carried over after a new citizen is born (replaces aqueduct = tradition finisher BOOM)
If those are overpowered, please tell me.
IF we were supposed to have Bandeirantes
Bandeirantes: comes with Drill I, gains production per kill to the nearest city, replaces musketman
(it could represent the natives capture. Instead of converting enemy barbarians into workers - which would, at that part of the game, become lame - you gain a production bonus equal to the enemy's strenght when you kill it. Let's say you are fighting a barbarian musketman (24) with a Bandeirante, and you are near Salvador. When you kill it, Salvador gains 24 production. It would work well)