Hi mharrington, nice work!
Wonderfull brainstorming you started. I’d like to add some fuel into the fire but as English is not my primary language I apologize in early for several mistakes I’ll make.
* Curitiba it’s a great city, a bit rainy but It’s people are one of the most polite in the country and, as a bonus, is near of Paranaguá port. In the past the city used to have a nostalgic train ride trough the rain forest connecting the city to the port. (Google for “curitiba to morretes train” images)
* Dream Street it’s a good choice since the word “whimsical” it’s pretty difficult to Brazilians to pronounce
* Brazilians do like collored stuff, so make the Dream Street a whimsical and happy explosion of color (see artists like OsGemeos / Eduardo Kobra). They also love to color rustic houses as you can see in this TV show: <
https://www.pinterest.com/victoriafifi/meu-pedacinho-de-chão/> or at turistic points like "Bahia's Pelourinho".
* Some mild attraction during the train ride would be great - Maybe one fun Night Beach Party inside of a tunnel (with A.A. Donald, José Carioca and others… Maybe stolen from EPCOT's Mexico pavillon ;-)). There is a LOT of amazing beaches in Brazil and this tunnel could be a magical passage to one of them.
* Soarin' (with a different closing, set in Rio de Janeiro) - Great! People love to go to “pedra bonita” to a Hang gliding ride. I’d add scenes of the warm “Lençóis Maranhenses National Park”
* Character meet-n-greed can also have the Aracuan crazy bird from "The clown of jungle"
* Jungle Cruise and the Rivers of America together it’s a very good idea, fill it with some plunges rafting style, people love a big and soaked ride, they will have so much fun during the summertime. Why don’t you add two more gods (earth and air) to complete the four elements found in nature?
* I didn’t see anything about a haunted place. You can add something like it in the Fronteirland using the Brazil’s colonial style (coffee farms, historical slaves quarters, abandoned theaters, old villages - seek for images like “City of Parati”, "City of Ouro Preto”, “Theatro Jose de Alencar” or “Teatro Amazonas”).
It’s all for now. Hope it helps you.
Regards,