Improperly directed maintenance procedures for a contract mechanic resulted in a second return to the gate; corrective maintenance; a timed out cabin crew; a canceled revenue flight and a ferry flight home for an A319 flight crew.

Narrative

During the second engine start and taxi out we received NAV STBY AOA FAULT. We referred to the AOM to see if crew action could be taken to continue flight. Maintenance Control advised us to return to the gate and Maintenance would meet the aircraft. The Contract Mechanic had a lengthy checklist of items to be deferred including collaring several circuit breakers. We verified these procedures with Maintenance Control. The logbook was signed off with standby AOA deferred and a downgrade to CAT 1 status.Due to this delay the Flight Attendants exceeded their duty day and were released; the flight canceled and we were advised to ferry the aircraft to ZZZ. During the second taxi out we received an additional status message on the upper left ECAM which stated when L/G (Landing Gear) Down DIRECT LAW. This message was not indicating at the gate as the engines weren't running. We notified Maintenance Control that we were returning to the gate again. Maintenance Control; the Contract Mechanic and the flight crew determined the procedure the Mechanic was instructed to follow was incorrect. The proper action was taken; the logbook signed off and we continued to ZZZ without further incident.