Mid year enrollees are automatically given the "Student" role, even if their enrollment date is in a later school term. This adds them to the class rosters before they are on campus and makes any reporting more difficult.
Just as employees who have a future start date are "pending employees" students with a future enroll date should be "Incoming Student." Mid-term enrollees would have their role automatically changed on their enroll date (again, just as a pending employee becomes an employee on their start date).