I think that actually these specific people would be a great choice for the Euro banknotes, because they are inspiring across borders. None of them are "national heroes". In Germany, we like Beethoven not because he was an exemplary German, but because he wrote bangers. In Germany, we look up to Marie Curie, because she won two Nobel prizes for cool research, no matter her nationalities! And they both migrated between European countries, like exemplary Europeans.