As for Alsace-Lorraine, we should note that it was created as a political territory in 1871, when Prussia sought to annex the areas that had German speakers and/or coal deposits. I'm not sure the circumstances (nationalism, industralization, powerful German state in the west) exist in the pre-1815 Europe for the statesmen to think of separating it from France. I think you would have change a lot.
Nationalism definitely exists; the French Revolution was driven to a large degree on it, and the 1848 revolutions were all about national-liberalism. People did demand the Alsace for Germany (i.e. the German Confederation) at Vienna; it was just those were people nobody listened to like activist students. But the sentiment was there, at least. Baden also tried to win the Alsace, and Württemberg Baden and Alsace both, but those were pipedreams by German middle/small powers. Even so, maybe some rearrangement could be done at Vienna, if the principle that the Kingdom of France is to be fully restored in its old borders is to be dropped.
Baden could gain Alsace, and in return lose Leiningen, Fürstenberg and its Bodensee territories (those weird appendages sticking out eastwards in the north and the south) to Württemberg, becoming a strip of land on both sides of the Rhine. And as for Bavaria, if it somehow gets less Franconia, it might be compensated with a larger area west of the Rhine... say, Palatinate, Trier/Mosel, Saar and Metz (and the Lorraine part of Alsace-Lorraine was basically Metz).
The only problem is that if the principle of the integrity of the Kingdom of France falls, I'd rather expect more territory to become German, like maybe all of the former Duchy of Lorraine...