I graduated from CMU, Mellon College of Science. Spring seamster and Fall seamster courses and different to some extend because most of freshmen start in the Fall. For example, Calculus I will be offered in Fall and Calculus II in spring. With that being said, not all students follow the courses plan for whatever reason (semester off/semester abroad/Spring batch (like you)) and eventually CMU offers a good amount of courses in both the fall and spring seamsters. Graduating spring or fall doesn't really matter, and you can catch up with the fall batch if you take summer classes. Maybe it will affect your internships because employers will have certain expectations in terms of course work from their previous experiences with the majority of students starting in the fall semester. I have no idea about your other questions. If i were you, I would contact the admission office to get in touch with a current student who started in spring seamster. Good luck