Since I know you're into Italian food, I would stick with that, as a way of welcoming them
into your family. Lasagna, manicotti, antipasti platters, whatever your family favorites are. Dessert could be a really nice selection of biscotti, cookies and bars.
The best suggestion I could make, since it's a lot of people, is to hire someone to come in, even if it's a teenage neighbor or someone's housekeeper, and help serve and clean up, so that you are free to be the hostess instead of being in the kitchen the whole time.