Re. (1): It can really depend on what they did before and during school. While in school, one could have real internships, real personal projects, open-source contributions, working for the university, contract gigs, etc.

Personal anecdata: I was solo building software projects in highschool that earned income (real product, creating real value, some of which were acquired) and worked on the school district websites. During college I contracted with startups part time while also building projects of my own.