How could that have gone if it was more successful? I mean, it's nearby, so it's not hard to pay for transportation, and it's a newly independent, impoverished, relatively weak country. Haiti was home to only about 800,000 people in 1870. Even only a million freedmen moving to the island could have made "Amerigo-Haitians" the majority.
Jean-Pierre Boyer seems to have been the primary backer of African-American immigration to Haiti but I think you'd need something that makes Haiti more attractive to African-Americans in the first place. A more stable Haiti under either Toussaint or Dessalines might last longer, though I can see Boyer attempt to establish a Black majority in a united Hispaniola under Haitian rule with these immigrants.
