Matt --

Aide-de-Camp -- an ex-officio position on a general officer's staff. Functioned as a personal aide to the general, and performed a wide range of duties, everything from carrying dispatches in battle to making sure the general had a place to bed down at night.

Assistant Adjutant-General -- the adjutant to a unit commander (from battalion to army level). Basically took care of the reports, official correspondence and other paperwork sent and received by the command.

Assistant Quartermaster -- the staff officer responsible for procuring and accounting for all supplies (except for rations) and equipment requested, received and expended by the unit.

Assistant Commissary of Subsistence -- the staff officer responsible for obtaining rations required by the unit.

Note that these last three staff positions were "assistants." The Adjutant-General, Quartermaster-General and Commissary-General were the heads of their respective departments in the Confederate War Department, and the end of the pipeline were the "assistants" in the field with the line regiments.