I'm curious about the Dutch reconquest idea. What is France doing when that happens? Does France get bribed with something to stay out of the conflict, or does this flame up into a general European war and the French are on the losing side?
All depend of how it managed.
If the revolution is crushed and William I put in place persecution against french and catholicism, a war would wappen.
If William II manage to be elected king of Belgium and accept to give a lot of guarantee to the Belgium after that both country are united a sort of compromise could happen maybe a sort of informal alliance and dynastic link with the Bourbons.
but it would be difficile to let him be elected king of Belgium.