One member of the court (the "jury") is a Marine captain, two pay grades below the defendant (a Navy commander), whereas the rules require that every member of the court must hold at least the same rank (or rate, if an enlisted person) as the defendant.
Chegwidden is required to use his excess leave. The government works on a July-June fiscal year. You can only carry 60 days of leave from one year to the next. This means that it must be June. The uniform would be whites, not blues.