Formal He should wear: A tuxedo or formal dark suit and tie. She should wear: A long evening dress, dressy suit or formal cocktail-length dress.
It depends. American, EU and Turkish passport holders don't need visa for stays less than 90 days. Check this link for more information: http://chicago.itamaraty.gov.br/en-us/visas.xml
We recommend flying and Uber. But if you decide to rent a car, make sure you ask for a car with a electronic-pass (called Sem-Parar) for toll ways. Google Maps and Waze apps work well in Brazil. If you don't want consume a lot of data while navigating we recommend downloading maps for offline use in Google Maps (https://support.google.com/maps/answer/6291838?co=GENIE.Platform%3DiOS&hl=en) Here is more information about general travel in Brazil: https://www.smartertravel.com/getting-around-brazil-transportation-tips/
We recommend checking with your wireless provider about roaming options since that'd be the simplest solution. If you want cheaper options compared to roaming, Claro and TIM are two local wireless companies that provide sim cards for your phone without requiring CPF (Brazilian national ID number). You'd need to stop by at their stores to obtain the cards and activate the services. There is no guarantee you'd find a clerk that speaks English other than the stores at the major airports like Rio or Sao Paulo.
https://visitbrasil.com/