Who is applying determines the answer to these questions.
A person who is AD USN is supposed to have a degree "in-hand" prior to submission, there are times that a person who will complete the degree after submission but prior to board meeting will be allowed to go to board, but this IS NOT the norm and can change when the director changes.
A person who is not AD USN can apply prior to graduation with a degree completion plan, in the past the rule was within 6 months, then it went to 12 months and then seemed to be slipping back to 6 months which might be due to BDCP being back.