(Authors note: all of these hypothetical situations exist in a universe where everyone lives and no one dies!)
Major: Chemistry. A hard science is really fitting for someone like Elphaba, who seems to be a bookworm.
Life on Campus: Elphaba was an outcast from day one. Aside from the obvious (green skin), her shyness didn't help when trying to make friends. A mishap in reslife has her sharing a room with Glinda, instead of her sister, and they're complete opposites. It's hate at first sight. *cue What Is This Feeling*
Major: Music. Specifically, she's a vocal performance (soprano) concentration.
Life on Campus: Glinda joins the school's acapella group (they always need someone to hit the high notes). She also rushes a sorority as soon as she possibly can. Glinda sees herself as the perfect, poised sorority sister. She thinks it'll up her popularity; she lives for attention.
Major: Political science. Fiyero is a terrible student, though. It's a miracle he's actually lasted an entire school year at the same school. He's really only at college to play sports, anyway.
Life on Campus: Lacrosse. It's pretty much all he does. Fiyero plays lacrosse, sleeps, and goes to frat parties. Glinda is obsessed with him, but he ran into the cutest green girl in the library (he doesn't even remember why he was in the library to begin with), and he's starting to think he should go to the library more often to find the green girl.
Major: Philosophy. Melchior literally doesn't even try. He tries so, so little and gets really high marks. He's already at the top of his class, but if he actually put effort in, he'd be the valedictorian.
Life on Campus: Melchior is in the library a lot either reading books by guys who have been dead for thousands of years, or writing something Moritz asked him to. He also likes house parties.
Major: Nursing. It's a rigid major, which fits the way Moritz tends to push himself. It's a good major for Moritz so he would be able to help people once he has a degree.
Life on Campus: Melchior would say that Moritz has the complete opposite of a real college experience. He's always in the library or his room (depending on when Ernst is in there) trying to memorize things for anatomy, or writing a paper for one of his other classes, or reading textbooks. He's known to get overwhelmed often.
Major: Literature. He's ridiculously good at school. He doesn't do any work outside of class and still manages a steady 4.0. Moritz is really jealous.
Life on Campus: Hänschen considers joining a frat for approximately two days. Eventually, he decides that it's too pretentious ("Maybe you're the pretentious one," Thea tells him). He's still super active on the "college hook-up scene", and he tries to ignore the disappointed and longing looks Ernst gives him in the dining hall.
Major: Psychology. Wendla has always been a hands-on learner, and she learns best through experience.
Life on Campus: Wendla is active in both the psychology club, and a philanthropy group (like St. Jude's Up Til Dawn), because she loves the idea of having fun and raising money to help people at the same time. She prefers to stay in on the weekends, having movie nights with her friends. Sometimes, Hänschen will convince her to go to a house party, but she won't go with him often.
The Book of Mormon:
Elder Kevin Price
Major: Church history. Kevin is very into his religion.
Life on Campus: Any religious club on campus, Kevin is a member of. He's a very independent person and he studies a lot. Kevin's outlook is that he wants to do something incredible that'll "blow God's freakin' mind".
Elder Arnold Cunningham
Major: Media studies. Arnold loves movies and film, so it just makes sense that he'll major in something movie related. He's also the best at writing papers at the last minute, having them make sense, and getting straight A's. He's great at making things up.
Life on Campus: Arnold is in any film related clubs on campus, and he's in the comedy club also. He likes to make people laugh. He jokes that he lost the roommate lottery when he got randomly assigned to Elder Price.
Jason McConnell and Peter Simmonds
I grouped Jason and Peter together, just because their lives in college would be always intertwined and extremely similar. In the musical, they both have goals to go to Notre Dame.
Major: Jason and Peter would both be theater majors, but Jason would have an additional business major because his father wanted him to.
Life on Campus: Jason and Peter would stay roommates in college, the way they were in boarding school. They do a bunch of school productions, and run lines together. Jason would probably have the same outlook on their relationship that he did in high school, at least during the first two years, while Peter's mind is slowly changing at the idea of being more open.
Jack Kelly and Katherine Plumber
Major: Jack and Katherine both major in journalism. Jack is also an art minor; he didn't start college as one but all of his friends and Katherine talked about his art so much he decided to add it in his sophomore year.
Life on Campus: Jack and Katherine are seen as the power couple of the journalism department. Once she took over editing the school newspaper, the entire thing turned around and people started paying attention to it. Jack is the assistant editor, and has a bunch of friends who help out with the weekly distribution.
Major: Elementary/Special education. He's probably really good with kids.
Life on Campus: Wherever Jack is, you'll probably find Crutchie nearby. He has an internship with a local pre-k, but other than that, he's usually hanging out with Jack. Jack has also been his roommate since freshman year and helps Crutchie out whenever he needs it. They take roadtrips together every spring break.
Major: Business/Political Science double major. He isn't sure what he wants to do when he graduates, but he does know that he wants to be a leader.
Life on Campus: Davey is a leader of everything he's in. He's the president of his hall, he's a senator at student government, and he's on the e-board of every club he joins. He writes for the newspaper also, and he's one of the people who distribute the papers with Jack.
Major: Women's studies.
Life on Campus: Tracy joins pretty much every activism group on campus. She's super into the idea of changing people's idea of "real beauty", because not everyone looks like a supermodel. She ended up going to the same college as Penny, but Link went to Los Angeles to pursue acting. Tracy and Link are making the long distance thing work, but the more it gets into the semester, the harder she's realizing it is between school, clubs, and fitting in some time to both call her mother, and Skype with Link.
The Addams Family:
Major: Mortuary science. It's fitting, isn't it? Wednesday has an obsession with death.
Life on Campus: Wednesday has a hard time making friends. She pretty much only goes to class and gets food, before hiding out in her room the rest of the day. Lucas Beineke transfers into her major in their sophomore year, and it's such a relief to finally have met someone who understands her. She wouldn't admit it, but she actually really likes it.
Major: Dance. His name is Lancelot, just watch him dance a lot.
Life on Campus: Lancelot is the only guy on the school dance team. He's the only guy that tried out, but he kind of expected that. He's in a pretty female-dominated major. Herbert drags him to Pride one day; lets just say Lancelot learns a lot about himself in the year following befriending Herbert.
Les Amis de L'ABC:
Les Mis is my absolute favorite, and I couldn't finish this off without writing about it/the students. Since they're all students with very detailed lives (Thanks, Victor Hugo), I've decided to imagine the Friends as a fraternity.
The Amis live together in a frat house a few blocks away from main campus. Enjolras is the president of the frat. It was a unanimous vote; he's a natural born leader. Combeferre has always been E's right hand man, so of course he'd be vice president. Courfeyrac is social chair but he also works really closely with Ferre and E; they are a trio to be reckoned with. Prouvaire takes on the role of new member educator when Ferre takes the role as VP.
Joly suggests that Grantaire becomes their public relations chair. R isn't amused by the idea, but it seems he is the only one not laughing at the thought. Joly's joke nomination turns into Grantaire actually becoming public relations chair. Joly is pleasantly surprised with the outcome of a joke, but he's even more pleased with the look Grantaire gives him -- it's the kind of look that would be red faced, ears steaming on a cartoon character. Even less amused is Enjolras, because there's fighting, but then there's fighting with Grantaire. It's a whole different level of fighting, and he foresees a lot of it in his future.
They're all very serious about their philanthropy (Enjolras is a certain brand of intense that is unmatchable by most), but because of Courf they're always having fun at the same time. His themed parties are matched by none, though many try.