Could "Plantation-Syndicalism" arise in an alternate Haitian Revolution; ie the plantations are own and run by the freeman and women who till the soil, and government is basically a branch of those syndics? Could syndaclism lead to a more prosperous Haiti?
Could you elaborate on what you're talking about? Having looked up Syndicalism, the descriptions seem pretty much just like Haiti tried OTL with a plantation economy.
After it gained independence, they tried having a worker-managed plantation system which was quickly uprooted by the Francophone elites, which in turn led to the plantation system breaking down completely as the workers simply refused to grow cash crops and took land for themselves, leading to a Haiti dominated by small-land ownership. I guess the easiest way to get the system you're talking about is to have the workers be the ones pulling the strings. That's pretty difficult, given that the Haitian slave revolt itself was promoted by the Francophone elite blacks who correctly predicted that with all the white people gone, they would be at the top of the new social order.
So you could go a few directions:
First, have the Haitian slave revolt be more about workers vs elites than race, so that the rich black people are also expelled after independence. This seems highly implausible given how the pre-revolutionary Haitian elites (rich white people) played the race card really well in dividing Haiti's poor whites and poor blacks; thus making race the primary conflict.
An easier solution is to have a worker rebellion occur at a later date. You could have the Creole-speaking population revolt against the Francophones and establish their own government which is more sympathetic towards the workers and embraces Syndicalism. But given that the Francophone elites are, most of the time, the only ones in power, it's pretty difficult to find someone to dislodge them. What might work is using the German-Haitians in the decades pre-WWI...