I read about that in the paper, I doubt his plan would work. It depended too much on other countries doing nothing and a revolt of the catholics that wouldn't have happened. No wonder France never wanted to support the plan.
indeed, Napoleon III specifically said to Leopold, he couldn't predict what his army would do in case of a Belgian invasion into the Netherlands.
And Leo's plans do seem more wishfull thinking then actual military planning.
Be in Amsterdam before the world could react?
and how exactly was he planning on crossing the Maas and the Waal?
What do you mean? Just Brussel speaking Dutch or also the language barrier more to the south? I have always wondered what areas in Brabant were originaly Dutch/Flemish speaking and what parts Walloon and when exactly it changed.
Both, more or less, Brussels would still grow beyond the tiny village it was and it would still become mostly French-speaking. But without Leopold pushing the development of Brussels, it would grow much less, swallow up fewer of the surrounding villages.
I seem to remember southern Brabant being mostly Dutchspeaking (though, actually drawing a fixed border seems rather impossible. Fact is, during Leopold II's reign, the fuzzy border moved north, almost reaching Brussels.
So, in TTL, there's a good chance Brabant will be Dutch with some mixed communities on the border with Namur.