I have to say this is a pretty good idea and would definitely spice up colonisation in game, which is one of CiV's worse features.
And, as a Portuguese, I have to say I'd love to see both Portugal and Brazil in a new EP.
Brazil is Portugal's ultimate and most proud legacy. We, the Portuguese, see in Brazil a sort of continuation of what we once were - and considering Brazil's astonishing growth, and considering it's the only nation in the America's capable of rivaling the US in some way (the "Great Two" of the Americas are the USA and Brazil), and because the United States is already in (and with due reason) it makes all sense to have Brazil.
Besides, Civ is not only about the past - it's also about the future. And if every BRIC country is already represented ingame, why not Brazil?
It will be one of the worlds future global powers. In fact, it already is.
I just think the OP rooster for Brazil is better than Rooftrellen's, desculpa parceiro

I hardly think that a police station would represent Brazil (a Sambodromo or a Football Stadium would better), or a "Thunderbolt" (I don't know about those, are they from Embraer?) is a good UU for Brazil. For all it's worth Brazil's military still lags behind those nations who have air force units as UU in the game (the US, for example).
The Bandeirantes would be the best UU for Brazil. Sure they represent São Paulo more than anyone, but they built Brazil, in a way. And considering what they did, well, maybe their special ability would be that, when conquering a single enemy worker, you'd get two. Or maybe, while being musketmen, they could build mines - just like the real Bandeirantes.
But, if someone disagrees the Bandeirantes are the best UU for Brazil because they were "Portuguese" at the time, well, then I'd say we should "create" an unit called "Soldados Imperiais" or something like that, from the heyday of the Empire of Brazil, post independence. But, all in all, the Bandeirantes would be the best choice.
As to the UA, well, it seems pretty good - and I think it actually reflects well the Brazilian spirit: Brazil is a massive "cultural nation" in its "golden times" (Bossa Nova anyone?) - but "Carnival" doesn't seem right to me.
"Order and Progress" or "Ordem e Progresso" surely gets it better and, come on, that's Brazil's motto, and it fits so well that nation trait.
As to the capital, Brasília is okay but it's a very recent city, and while it represents Brazil's present and future it doesn't represent its past. It is less than 50 years old.
Rio de Janeiro has to be the capital. Brazil's oldest city and the capital of the Empire of Brazil and, for a time, even the United Kingdom of Portugal and Brazil.
Rio is Brazil's heart and soul.
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Brazil (Delux Edition)
Leader: Dom Pedro I
UU: Bandeirantes (Musketman)- slightly more expensive, can improve resources like workers
UB: Sambódromo (Stadium)- in addition to regular stadium benefits, The Sambódromo grants +2 gold
UA: Order and Progress - +15% culture when the empire is happy
Capital: Rio de Janeiro
Colors: Dark Green and Yellow