First things first: Thanks to all of those who posted Rio in the past several months. I planned many a meal around your recommendations- Sambamaster, Vinhotinho, etc.
What follows are a few additional comments, recommendations and confirmations of your good judgement.
Bar Do Mineiro- great place for drinks or a big plate of food anytime. The pork chips are excellent. The carne de sol (dried and shredded beef, something between pastrami and beef jerky) is also a fine choice.
Two doors toward the square on the same street you will see a little bar perched above street level. I found this a nice place to watch the street life and enjoy one of the fine craft beers on offer. I cant recall the brand name but this place had the best selection of any bar i visited in Rio.
Library/Cultural Center- Just opposite and above the "square" is an excellent place to drink beer and eat pizza. This large rambling house and maze-like garden always has something going on. Live music, performances seem constant. Pizza is always on offer but there are also sometimes Brazilian buffets set up in the right side hall. Great vibe up there. Nice people.
Bar do Arnuardo- Another little neighborhood institution. This place doesnt have the same historic feel (like Bar do Mineiro) but I thought the food was better. I had the pig intestines and crackling stew cooked in a clay pot one night and came back for it the next day.
Bar Do Marco- For me this was one of the most appealing taverns of the neighborhood. The food was just fine (I had the trout plate and assorted pasteis) and the room itself is lovely. Funky colors, warped floors, view into the shanties below from the back balcony. Good live music regularly.
Bar Gomez- near the end of the trolley line is an interesting old corner tavern. Nice fried barsnacks (i got the cod balls) and cold bottled beer. The interior of the place is absolutely authentic, perhaps to a fault. it almost feels like it is intentionally preserved for the sake of the tourists. still, there were plenty of colorful, rowdy locals in there when I was there. and plenty of tourists snapping photos. it is worth a stop.
Aprazivel- I had high expectations for this place. Many people recommended it emphatically- the view! The cocktails! The regional Brazilian cuisines gone haute!
The cocktails on offer were a bit more varied that usual. they do a mixed fruit caipirinha. i stuck the the classic model and was not disappointed. Though it wasnt much different from the one i had mixed for myself at the hotel earlier that day.
The view! i didnt see any tables with much more than partial views. there was a sort of treehouse structure that i didnt check out but, i'd say, views are not much of a draw for this place.
The waitstaff was the pushiest we found in all of Rio. Our waiter spoke fine English but chose to make recommendations without explanations. always the most expensive in the category.
The heart of palm appetizer was nice and smoky. The roasted goat was tender and plentiful.
The food, in general, was not much better than what we ate at the Siri Mole kiosk down in Copacabana.
We were looking for a more elegant place to eat that night (not a tavern atmosphere) so Aprazivel served its purpose but I wouldnt recommend it for much more than that.