Help with names?!???

There's 2 boys, Gino and Marco. We need middle names for both of them, and we'd like them to be Italian derived. We don't know the last child's gender, so we'd like to have a good idea of the name. If it's a girl, I liked Natalia. If it's another boy, I thought of Luca or Sebastiano. Can someone help us with middle names for all 3, and a first name for the last? Thanks!