I just got from Nth Brazil. I only went as far south as Salvador. But there wasnt much wind there, but plenty of swell for surfing. I was told by the locals that the best carnaval is the one held in Salvador not the one in Rio. The reason is that you can actually partake in the Salvador one, while the Rio one you only watch from the sidelines.
In regards to kiting, I hear there is some good wave riding to be done down south, especially around Santa Catarina. But this is a fair way south of Rio. Not sure what the wind will be like at that time of year. Do a search on kiteforum and you might get some answers. Cheers

With regards to the "Carnaval", go to Salvador. Rio is only good under three circumstances:
1. You're not single
2. You're partner is there with you
3. You have access to one of the good "Camarotes" (Huge private boxes). Recommended is the "Camarote da Brahma"

You can kitesurf around Salvador. Praia do Forte and Busca Vida can be good. But if kiting is your main priority go further norht to Fortaleza (even though it's pretty much towards their down season, you're more likely to have some wind around there).

But if your main focus is the Carnaval. I would recommend 2 days of Pre-Carnaval (Friday and Saturday). Then the 3 main days (Sunday to Tuesday). Don't go for the Barra-Ondina on the main days (FYI: there are two options. One is Barra-Ondina. I forgot the name of the other one).

Make sure you find out which "Blocos" are hot this year. Normally it's Asa de Aguia, Banda Beijo, Chiclete Com Banana or Nana.... Then buy the necessary "Abadas" (your right to party in that bloco (normally you get 3 T-shirts and 3 shorts in the colours of that bloco). The good thing about having purchased the "abada" from one of the top "blocos" is that you can trade the T-Shirt/Shorts for the second day for one from another bloco (Just in case you have snogged all the 2,500 girls that are in one "bloco" - average size of a bloco is 5,000).

You can find some information on www.centraldocarnaval.com (not sure if you need a .br).

Have fun. I've been to Salvador 9 times and to Rio 3. No doubt Salvador rocks.

After the Carnaval you should go to either Morro de Sao Paulo where the party goes on (this time more at night) or to a place like Trancoso. I personally prefer Trancoso. It's a pretty special place.

Anyway, all the best and have fun.

M