If the events leading to this happen after Cuba, I expect the US will head off any potential revolution by whatever means they have to. Plus, while more communism in the Caribbean is generally a good thing for the Soviet Union, Cuba was the prize, I don't think they'd throw their full weight behind Haiti and risk a war over it.
If this revolution precedes the events in Cuba the new communist state might survive. But the problem is that while Cuba is an island by itself, Haiti has the DR to its east. So the DR is going to have to figure out how to deal with the new government on their border. If the US takes the lessons from this 2nd Haitian revolution then there might never be a Cuban revolution in the way we recognize it. The intelligence services would just be too focused on the region.
IOTL something like 20% of all Haitians live abroad. I would expect that percentage to increase if Haiti has a sustained communist revolution. Maybe as high as 30-35%. But the number of countries willing to take Haitians is....not particularly high. If this takes place during Trujillo's tenure as President of the DR you could actually see very violent methods used to keep Haitians out of the country.