I'm always pro-domesticate, just because I like the idea of Native Americans resisting colonization. Pronghorns are not likely to be suitable, though. Too prone to flight, and not a lot of meat on a body built for speed. It would be cool to have more of them around, though.
Just some thoughts: You might see the Marsh Deer and the South American tapir go extinct, as they like wet habitat and the bamboo seems to dry things up. White-lipped peccaries, which like moist forests, might also see a dramatic reduction in numbers.
So the question really is, what can thrive in a dryer environment? Grasslands would be great habitat for pronghorns and any animal that eats grass and course vegetation. The Flat-headed peccary would also benefit from the increased dry habitat. Browsing animals could also benefit from more open forests, which gives them more room, lets them spot predators more easily, so shrub oxes and Hemiauchenia macrocephala (the large-headed llama) could survive in North America's southeast.
Slower-moving, larger animals will still lose out with pressure from human hunters, so I think ground sloths and pampatheres may lose out-though the Pampathere's ability to eat coarse vegetation would help them survive in the the larger open grasslands of South America.