Let's see if I can help clear this up...
I went to university/college in the US (undergrad in the 90s and grad school in the 2010s). During grad school I was also an adjunct professor hired to teach one course, as my professional experience made me better qualified than anyone else on staff, or so they told me. From those experiences and the experiences of many friends who went to college in the US, I can verify that some schools are very difficult to get into (either they have strict academic standards or they limit their numbers for other reasons, such as wanting to maintain a small teacher-to-student ratio) while others are exceedingly easy to get into (schools with "open admissions" policies require only that students have completed high school or the equivalent). And, of course, there are many schools with admission policies somewhere in between these extremes.
Some universities are still on a quarterly system (fall, winter, spring, and summer), but to help cut administrative costs, most schools are now on a semester system (fall, spring, and summer). B&R appears to be on a semester system. Typically, most students begin their college careers in the fall (late August or September), as they graduated high school the previous spring/summer (May or June). Students can also begin in the spring or even the summer, but this is atypical.
Students who show up a bit late or for whatever reason are unavailable on day one (like Josy and Lily) can generally enroll for classes up to two or three weeks after the semester starts. A student would not be allowed to start classes much later than that, for several obvious reasons. We know that in episode 8, MC et al are taking midterm exams, so that means that approximately 7 or 8 weeks have passed (typical US university semester is 15 weeks). This would be too late for any new students to enroll. They would have to wait until the next semester, which at B&R for our purposes would be the spring semester.
The fall semester will end in mid December or so, then students will be off for the year-end holidays (many campuses even close the dorms, requiring students to leave campus). The spring semester then kicks off in early to mid January.
Schools do offer courses during a condensed summer semester, which usually runs June to August, but most US students do not take summer courses. US universities schedule courses in a way that most students will not need summer courses to complete their studies. Instead, most students spend their summers working jobs, doing internships, or (if they're wealthy and priveleged enough) traveling and otherwise relaxing.
Life itself is an unnecessary filler before the endgame which death . That's the endgame. Whats matter, is how your "filler" is enjoyable. And Interlude was genuinely enjoyable. same as DnG. The only filler that was not enjoyable is Madame
