1. I left the Rhine border a bit vague as it would open several butterflies. But without Bismark, I think that Alsace would be a fair price for France's support in building a unified Northgerman state. Something that Nap III and Willi I could both accept.
One could argue that Napoleon III could have pissed of the Prussians by demanding more. This would lead evt. to a conflict down the line, probably with Willhelm II. But there is now a North-Germany, some independent Southern German states and a weak Austria. There are more gains in appeasing France and taking the rest of German speaking Europe. After that, a unified Germany can still go for the "French part of Germany". Also, nationalism being what it is, would cause France serious troubles - revolutions.
Without Bismark there would be nobody to stop Willhelm I from taking pieces out of Austria. I think that they would have no choice but to give Italy ALL the Italian speaking parts of Austria -something that France would ask for, even if Austria defeated Sardinia Piemont initialy. Austria would be left weak and ready for unrest, joining the Ottoman Empire as the weak men of Europe. thus leading to the eventual collaps from within and the annexation of the German speaking parts of Austria to the German Empire.
2. I would go with the - or very close to - the 1914 borders, thus making the 1866 war between Italy and Austria unneccessary and removing the dispute with France. Maximillian was far more intertested in Hungary and Bohemia - were the money was - and realist enough to know that if he keeps some part of Italy he only asks for another war. Plus it is a small price if it gives him peace and friendship with France.
By 1866 the French-Austrian alliance would be firmly established and Italy would stay out of the war, having no gain from it. It would be more interesting for Italy to seize the Papacy while France is busy in Germany, but that is another story.
The Großdeutsche Lösung would follow eventually with the fall of Prussia - Willhelm II would have gone to war with Austria-France, even and probably all by himself. This would have given Austria the opportunity split Prussia appart and to form a different Germany , very likely a more federal union than the "original", perhaps a United States of Germany with Bohemia, Hungaria, and the Balkanstates as Free-states within.
That would of course depend on how old Maximilan will become. If he reaches the same age as his brother he would make it until 1918. Enough time to establish a USG.