You should also have favors match the tone of the wedding. Formal weddings call for very elegant favors while casual outdoor weddings may not. If matching favors to the theme is too difficult, try matching colors.
Having a legal ceremony in Italy isn't exactly straightforward, so prepare yourself for quite a bit of paperwork, and a bit of back and forth with the local mayor. But I've done some of the initial work for you and pulled together a handy list of all you need to know, including the process of organizing a wedding in Italy, and all the paperwork you'll need for a religious or civil ceremony. It is totally manageable, don't worry, just have a read and get started. It will all be worth it!