ImperialVienna said:
Sophie and Napoleon II only met after Sophie had married Franz Karl and was living in Vienna - I know, Sophie was my first thought too.
Well, in a Napoleonic Victory scenario, it is possible to have Napoleon II marry Sophia of Bavaria : from what I read, her wedding to Franz Karl was only decided during the Congress of Vienna

.
However, if we go OTL (Napoleonic defeat thus), then that marriage isn't plausible unless Franz Karl dies first. Sophie was very close to Napoleon II though in her lifetime : if the Eaglet were to live longer, she could probably stay as a good friend of him.
Besides Sophie of Bavaria, the other women I could see Napoleon II marrying would be :
-A Hapsburg princess or Hapsburg-related princess. Napoleon II was after all a granson of Francis I of Austria.
-A Bonaparte princess or Bonaparte-related princess. He is Napoleon I's son after all.
-A Bavarian princess : the Bavarians were one of the most Bonapartist states during the Napoleonic Wars.
-A Beauharnais princess : Eugene de Beauharnais was Napoleon I's stepson (being the son of Josephine, Napoleon had adopted him) and had married Augusta Amelia of Bavaria, an older sister of Sophie.