No one arrives on time. Never. Ever. Arriving at 10pm at a party is the best way to announce your gringoness. Also, Brazilians tend to party until late. Get ready to arrive around 11:30pm and leave after 4am.
The rule for beer and most beverages is very simple: the colder, the better. Brazilians drink ice-cold beer. Mainstream brands all taste the same, but it’s been increasingly easier to find local brews, especially in the South / Southeast states. Give it a try.