Genghis could still be released alongside the Qing, maybe even Mughals?They've already as part of the marketing for this game said that it was a mistake to release a civ game without Genghis Khan, so he's presumably in, but we've already seen Mongolia. If they don't announce Mexico with a matching leader, it might lower the probability but not to 0.
As far as the Americas go it is just Mexico and America, which the latter will have Ben Franklin, so I would put those chances of another leader from there lower than other parts of the world.