3) Spanish colonies mostly immediately freed the slaves. Brazil didn't, and Cuba remained a colony, so they're the ones who had slavery after the US South had to give it up. Mostly, however, blacks were kept on the lower rungs of society. In the Caribbean (again, Spanish America isn't as important in terms of black slaves), coolies were often brought to work in their stead. Of course, in Haiti you have the black rebellion, of which Cubans, Americans, and Brazilians were deathly afraid.
4) In the late 1800s, all countries in continental S. America incentivized European immigration to "whiten the race." Argentina, Uruguay, and to a lesser degree Chile were the only successful ones.
5) After traffick but not slavery was abolished in mid-XIX century Brazil, trafficking became so lucrative that the dealers, mostly American, were willing to use clippers as disposable assets. They'd ship from Africa, unload in Brazil by beaching the ship, and then burn it so there wouldn't be any evidence
Heh. That's kind of a big subject, so I'll just throw a few random facts now, and promise to be more detailed on Monday.
1) Remember that black slavery was basically a Brazilian and Caribbean thing. Argentina, the US, or Pacific Hispanoamerica were completely marginal. Each of Brazil and the Caribbean got five times more slaves than all of those areas together.
2) Yeah, there were a lot of escaped slave communities (quilombos, im .pt, cimarrones in .es, maroons in .en), and they intermingled with the local Indian tribes to some extent. To this day, you'll have indian tribes with African features in the Brazilian NE. The largest of them, Palmares, lasted for over a century and was the size of a middling kingdom of the time.