On the teacher-classroom worksheet, do you need the teacher's full name in one field, or should it be broken out into two fields (first and last names)?

You can do it either way, whichever is easier for you. If you put the whole name in a full_name column CP will split it into first, last, middle for you when creating the teacher. The rules to make the split are pretty robust, but it is possible that part of a person’s first name may end up in the middle name field (i.e. Mary Ellen Smith, Mary would go into the first name field, Catherine into the middle, and Smith into the last, instead of Mary Ellen all being placed into the first).