Your questions A and B and good, and valid, but very difficult to answer. Each and every class, professor, and institution have their own requirements and expectations for the writing quality of their students. Assigned reading is also very dependent upon the professor, course, and subject. For example, science majors might be required to read published journal articles while philosophy majors would be expected to read works by Kant, Plato, Descartes, etc. Beowulf might show up in mediaeval literature classes as well as mediaeval history classes. In foreign language classes you will find short stories in German, French, Spanish, etc. which gradually get longer as you progress through each level. And each course will also have a textbook, naturally.
C. Sit wherever you are most comfortable and productive. Some sit near the front so they can see the board better and hear the professor more clearly (while also resisting the urge to day-dream), but some might find the back to be less intimidating. I always preferred the third/fourth row in large lecture halls. Sitting with friends isn't always the best idea, but in some classes it's okay (like PaleoBio).
Hope that helps, and best of luck.
