Guava is nice. But there are many amazing fruits. Try cajú as a drink, the cashew fruit, not the cashew nut, the fruit. Maracúja is also great, or carambola. Pitanga is also something to try and many many more fruits. Countless thinga to try. Enjoy the stay.
Sorry for the late answer... busy days. See post above. And, sorry for the double posting. Somehow your answers didn't appear or I overlooked them, and I didn't receive a note that you answered to me xD
I lived in Brazil for a couple of years. Some nice places around. São Paulo is nice for a while, but a really huge city. Great gastronomy. Largest Japanese community outside Japan, so the restaurants are great. You find almost every type of culinary in São Paulo. In addition to the big cities, I would recommend to visit the countryside and do some hiking. Brazilian nature is beautiful. Be sure that you have mosquito repellent with you in the countryside, dengue and zika are still an issue. Safety is an issue in SP and other big issues. Avoid night walks alone in certain urban districts. I could write a lot more... well, if you want some more information, Just text me. I know many places from the far north of Brazil to the far south.
Where exactly in South America do you wanna stay? Depends where do you want stay...