Oh, that's one part of the Brazilian uniques that I didn't mind much. I don't know if it was caused by ignorance or by conscious choice, but I take it as a gameplay decision. It seems to me much more balanced to have a jungle UI than a forest UI. Or you people expected to see Brazil as anything but a jungle civ? I actually took for granted we would see some of the stereotype of "Brazil-jungles-bananas", heh
The Carnival thing did bother me a little, as for Pedro II's reign, we could have some cultural bonuses arising from different reasons, like his many translations and correspondence with intelectuals and scientists throghout the world (
http://veja.abril.com.br/280410/razao-tropicos-p-118.shtml). But, mechanically speaking, the Carnival seems an interesting choice - it's just a bit strange to have a Carnival every 3000 years or so.
PS: I'm feel ashamed of linking something from Veja, but hey, the were quite sensible in this article.