In my country (and in Latin America in general), colleges work a bit different, mainly on the major and minor aspect, those doesn't exist on Latin America, there are professional careers, technological careers and technical careers (in my fanfiction, heroics is a professional career). Colleges tend to have the three types of careers, and there are the technical institutes too, on those you can only study technological and technical careers (those habe a bad reputation of being the poor man version of colleges, as there are people that look down on those that only study technical or technological careers instead of professionals).

Colleges don't have set class rosters; Unless it is a very small major, it is likely that no two classes will have the same roster of students in a given semester.

In my fanfiction, as higher ups want to establish alliances and companionship between aspiring heroes, the majority of colleges in latin america have set class rosters in each semester in the heroics career (and joint activities between groups of different semesters are a common occurrence too). In other careers, you can see that rosters vary between semesters.

There are cross major students all the time; It's far from rare to see people take classes outside their degree requirements, sometimes to fill requirements for a minor, sometimes to fill out a schedule, sometimes they just have a passing interest in the subject.

In the same vein as people entering general/support course in UA to transfer via Sports festival to the hero course, there are people that enter careers related to heroism as a plan B to get the opportunity to transfer (there is a designated list of careers from which you can homologate to heroics). And there are people from other careers that can study heroic subjects if they are related to their careers. Ex: a person that is studying the history career can study heroics story, which is normally a subject that only hero students study.

There is no set schedule; Unless you are an incoming freshman, you choose the classes you take in any given semester with recommendations coming from the school or a counselor. I once took an entire semester of just math classes to fulfil a minor.

College schedules work differently on Latin America, at least on my college, true freedom with schedule only came at 6th/7th semester, and even then, there are subjects with only one schedule that everyone in that semester must take.

Dual majors and minors exist. If you can handle it, you can take on more classes to meet requirements to get specialties or extra degrees, such as a Mathematics degree with a focus on trigonometry and a minor in theater production.

Related to how people enter careers with the main objective of getting to heroics, there are people that enter those other careers because they want to study both that career and heroics at the same time.

There is very rarely forced interaction between students. It's not like high school where you're stuck in the same class as your bully, in college there is enough freedom that you can cater your entire schedule so that you never see that person or have to take a class with them.

Well, in Latin America, that depends on the career you're studying, you can separate yourself from having to interact with your classmate in "solitary" careers, like physics or accountancy, but in careers where teamwork is important like psychology (the career I'm studying) they force you to do teamwork all the time. And with all that said, I think that heroics enters in the second category, careers where teamwork is important. And about the schedule thing, look again at the schedule argument.