1. Antonio, Andrea, Marco, Roberto.
2. Yes.
3. No It doesn't.
4. No but other names do.
5. Yes, Rossi, Bianchi, Esposito for example.
6. Andrea, it depends on the situation, at work always surname, outside, if are friends of my friends of course I think I can use their first name.
7. Yes, At work or for students to be shorter and faster.
8. Cicci, patatina, ecc.