You're really making mistakes here. The irredentist claims of France encompassed all of Belgium (including Dutch Limburg, too), and there was no Wallonia to speak of. The liberals who rose up against the Dutch weren't based in Wallonia, as a matter of fact Wallonia was more Orangist than Flanders. The entire bourgeoisie, all over the country, was French-speaking. Regular Walloons didn't speak French, they spoke Walloon. The organizers of the 1831 and 1841 coup attempts were conservative Walloons.
To sum it up, the Catholic hierarchy was displeased with the Northern government. The liberals disliked the Orangist regime, and a minority of people in Brussels wanted independence. A minority of liberals in Brussels organized the revolution and once the Dutch retreated, the rest of the country decided to support them. But the Belgian independentist movement wasn't a Walloon one, and one the reasons the Belgian army fared so poorly against the Dutch during the Ten Days' Campaign was that conservative elements - French-speaking people as well - supported an Orangist restoration. The sides of the Belgian Revolution had no linguistic divide, Orangists and independentists both spoke French.