Since the College does not interpret Withdrawals, (which appear as "WD" on student records) as equivalent to failing grades, they are not calculated in any way into their College GPAs. "WD" was never meant to be interchangeable with "UNS" (unsat), "F" (fail) or "E", which are the only codes on a student record that denote a failing grade.
As to incompletes, this is denoted by "ABS" in a student's record, and would eventually turn into an E or UNS unless followed by a pound sign, such as "ABS#", which means a make-up exam was granted in a course (which, once taken, if passed, would turn into a letter grade or a "P" (pass) or "SAT").
If course work was incomplete but a student was granted an extension, that would appear on their record as "EXT" in the grade column, and would also turn into a grade once the work is graded. And if there is no entry in the grade column for any course on a student's record, it simply means the course head has not yet submitted a grade.