Can this result in a sort of Spanish civil war? I mean, if the Prussians have Leopold actually claim the Spanish throne for himself, the French can try to back up other pretenders like future Alfonso XII? Aside from that, like the others have said, Austria and Denmark are possible allies for...
Having Junior marrying into the Orleans line doesn't really help - they will still see him as a threat, which he is, and he is supposed to keep the French power in check. Besides, it will harm his image among his supporters. Austria will be his major supporter and I can even see the Austrians...
I meant that most likely Napoleon Jr. only gets to be King of Belgium if he abdicates from any claim on the French throne for himself and his descendants. At the very least, I can see some of his opponents insisting on it. Assuming he agrees and gets crowned as king of Belgium, his supporters...
The Republic may still get succesful enough to establish Rhein border and conquer Belgium plus, probably, establish sister republics in northern Italy, Holland and Switzerland. With the Republican France being the mess it is, someone like Hoche or Moreau (or, who the hell knows, mayhaps even...
First Republic can still end OK with other talented generals stepping in and possibly taking over. Sure enough, they are not nearly as succesful short-term wise, but that might result in France being better off in the long run.
Biggest challenge with the Eaglet is having him giving up his claim to the French throne. Than again, if there are certain not so moral people in his inner circle, they might even talk him into it and use Belgium as gateway into France. There are a lot of Bonaparte sympathizers and the new...
Mayhaps, have Hoche, Kleber and Desaix survive (all three were pretty loyal to Napoleon and quite skilled) and have the Emperor induct several new, younger marshals around the beginnig of 1810s?
The Empire could have survived, but some PODs have to happen. Be prepared to face Prussia, avoid getting bogged down in Mexican adventures, marry off your heir to the British (as far as I remember, a marriage between Napoleon IV and princess Beatrice was on the cards for quite some time). It is...
Napoleon can agree to the Frankfurt proposals. Another chance would be at the battle of Leipzig, where the day before the battle the French had a solid chance of capturing the allied monarchs.
Napoleon II has a chance, in case his Austrian grandfather has a clash with Louis-Philippe and decides...