It's mentioned in the film that Brazil has the largest Japanese population outside Japan. This is correct; there are an estimated 1.6 million people of Japanese descent in Brazil, making up around 1% of the population.
The real location used in the movie for the favela is not Rio de Janeiro, it's "La Perla" neighborhood from Puerto Rico!
To add info regarding the attempted suicide scene at the beginning, the rounds put into the shot glasses are 9mm semiauto-type rounds. Yes, the primers do show the ammo has already been used and failed to fire. Perhaps this was intended by the character in hopes the ammo might fire subsequent to a prior failed attempt or attempts. MJW then loads two of the 9mm rounds into a Smith & Wesson Model 66 revolver. This revolver is a .357 Magnum caliber revolver which will not work with 9mm ammo.
Laila Ali former boxing world champion does not have a single fight scene.
Laila Ali Daughter of Muhammad Ali, and Verónica Porche Ali.