To clarify about some Brigade/Regimental positions.
Certain billets/staffs are picked via their officer counterparts and don't have the same Brigade Board that one would have for other Brigade/Regimental billets. It is up to these officers to nominate individuals to the Deputy Commandant, who forwards the request to the Commandant. Usually this is a separate application process. An example is the Honor and Character Staffs; Physical Missions (NAAA Staff), Foreign Affairs Conference, Leadership Conference, Athletic Teams Commander (NAAA Staff), YP Squadron Commodore (Seamanship & Navigation), SAVI/CMEO, ADEO, Protocol (Social Director), Intramurals (PE Dept), MISLO (Bancroft MIS Officer), Religious Command Program (Chaplains?), MAG billets.
Certain Brigade level billets are assigned to Battalions to fill after dissemination of the main striper list. Some Battalion Officers ask Company Officers & SELs for their input in recommendations. The billets rotate battalions on a semester basis, so that a specific billet isn't always coming from one battalion.