First off, it's Couronian, not Courish. It might not be ASB, but it would be difficult, and likely be a colony in name only. As in, the local rulers basically accept the duke of Courland as their sovereign and Couronian traders get preferential treatment. Not much more Courland could do unless it gets a huge population overnight.
The meme becomes real.What would happen to the colony after the Partitions of Poland?
If the Courish colonies in the Gambia never fell to the British, what would the Gambia be like? (Please tell me if this is to ASB).