The issue is that slave liberation did not work, for the historical example is Haiti where those in charge wrecked the country (course did not help that every country was against them and France put blockade on them till they got paid.).
The issue is that in beginning the cash crop that going to provide $$$ and lots of money is sugar and unfortunately that is brutal and grueling work (dangerous too). This was one of the reasons that Haiti collapsed after the revolt. They had nothing to sell for manufactured goods. You also need to attract teachers and trades people to train your people.
Plus you live in the worse possible place for Europeans to survive with short life expectancy in the caribbean.
It is a hard push to connect slave liberation to wrecking the country. Plenty of states that weren't previously slave states had the same problems.
There is also a significant difference between Haiti, and the proposal of liberated slaves piloting slave ships.
One, unlike Haiti, we've got at most the trauma of capture and shipping, rather than a lifetime. That creates a distinctly different set of grievances.
Two, again unlike Haiti, this isn't exclusively liberation from one country (though Britain certainly loses a lot of slave transports) which means that unlike Haiti, there is no one country that wants to come and reconquer their slave state. There is a different problem that whoever has lost control of territory has an issue, which is a more dangerous problem, but less organised.
You are right though, you need to attract teachers and tradespeople. Now some now-former slaves would have experience in that role as they weren't raised as slaves. However there is good reason to transition from just pirates to a larger society, and that makes a big difference. A tax-less society has plenty of things to attract someone, especially if that society is SAFE. (That being the vital challenge). This is where the economy of Nassau would have to come into play. We can (to a point) assume plenty of incoming loot, distributed with the pirates, meaning that there is good potential for bars, suppliers of food, booze, etc. If smugglers get involved, or traders that are able to be on good terms with the Republic and its neighbours, there is a potential for a trade economy to start up for outfitting and supplying the pirates, and then the freed slaves. The economy, outside of a centre for manufacturing that out of the control of any government, is a question and atm I can't find any real details for its economy outside of Piracy (and sponges, but I'm not sure sponges are the best economic base).
If Nassau is able to grow sugar, then there is a potential for plantations, but they'd likely be radically different if the Republic didn't have slavery. Which has some benefits - if you don't have to buy the slaves, that is a cost reduction, and whilst it'd be less profitable overall than more typical plantations, it would certainly be viable. (Just depends on whether or not Nassau or the Bahamas could support it). The trick is whether or not it is consumed locally, made into rum, or exported, the latter being a challenge until the Republic is recognised, with the idea of its territorial waters being something to respect (and therefore sailing through without permission being seen as just cause for capture). All hard asks, but I could see it being sold under different names. (i.e. John Smith of Cuba, not "Nassau Sugar Commune of the 500 sisters".)
While that certainly would help, i think there would need to be a bit more of a history/precedent for these pirates to look to, and there is a situation that'd dove tail with a better off french new world: a Jamaica that goes rogue during the English civil war (which really should be called a revolution).
Remember, when the English took the island from spanish hands it was done by a motly crew of political dissidents and undesirables. Now in our TL they were mostly royalists sent by the commonwealth/protectorate government, but if they had been more composed of people like levelers and diggers, people that are already viewed as proto-anarchists/agrarian socialists/Christian socialists, you could have them try and strike out on their own with the restoration.
They probably wouldn't last very long, maybe five years or so before being forced to submit yo the crown again, but it would leave a mark on people's psyche
That does sound really cool, I like the idea of diggers and levellers getting more love. Especially if some of them survive and have a legacy - diggers and levellers making their way to the Republic could be a really good PoD.
What I really like is the potential for a "Return" idea. Nassau is well and good, but it isn't a large place. If the Republic can organise, and then ally with/find cause with the natives of Jamaica, they could repeat that invasion, and relocate the Republic in Jamaica, which is a much larger place to develop the Republic and have it survive, with a great central location for causing havoc in the Caribbean if they are involved in any wars.
It should be said that pirates oftentimes sold the slaves they captured.
Yeah, that'd have to be a PoD - it is why I suggested Blackbeard, as he had ~1/3 of his ships crewed by freed slaves. If he can effectively bring enough free slaves to Nassau to have that make selling slaves intolerable or sidelined at the very least on the island
Especially when death toll was high and there was a high demand for sales from sugar plantations who not care where their slaves come from.
Yeah, that is the temptation, but it's also the weird feedback loop the Republic has. If you have freed slaves working communal plantations, but at the same time, enabling the capture of more slaves, it makes slave-run plantations more expensive as you have a solid risk of losing your slaves, making the communal plantations a more viable source of sugar. Oddly enough that COULD hasten the end of slave-run plantations.