A321 Captain reported communications issues caused lengthy delays and a fatigue call after load shedding interfered with engine start and push back from the gate.

Narrative

Aircraft X began with a report time of XA:15 local time at ZZZ with a destination of ZZZ1. Upon maintenance logbook review; two items of note were the INOP APU [for oil quantity I believe] and a #2 engine igniter INOP. These MEL items required an engine start at the gate with external air cart and a manual start for Engine #2. Aircraft was blocked with Engine 2 started at the gate under guidance from Section X reference material. Unable to cross bleed start in the alley the aircraft repositioned for a 'Cross bleed start' to taxi for departure. At this point the inflight called forward to inform us of a loss of all electrical power in in the cabin and trouble using the interphones. The galley power had shed and was only indicated by a note on the electrical page of the ECAM (Electronic Centralized Aircraft Monitor). As per procedure I made a call to Dispatch and Maintenance Control for further direction. A description of the events was given to Maintenance Control and I asked for their direction to restore the galley bus. Under direction of Maintenance Control; I reset Sec 1; 2 and 3. I am unsure why the SECs would be used for the solution; but I defer to the knowledge of MX (Maintenance) Control. I never attempted to start the remaining engine which may have cured the problem; mostly because of the trouble with interphones and the unexpected galley issues. The call to MX Control was to get help in assessment of the failures and to find an easy solution. The reset was unsuccessful and Maintenance directed me to return to gate have the local maintenance fix the problem. Which to me indicated a larger aircraft systems problem. In the hour of troubleshooting; the customers were left without air-conditioning and the cabin reached 90 degrees with many of the customers complaining of the heat. A water service was started by the inflight. Back at the gate Maintenance was unable to reset the galley power by normal procedures and worked on the problem for one hour. The solution was to start both engines and the INOP APU; which MX started while still on MEL [the MEL was never cleared] at the gate along with a reset of the galley bus to restore galley function. I was told push off the gate with both engines as the solution. The aircraft was boarded and customers seated so we closed up received a new release and fuel summary for block out. The flight blocked out at XB:12 local. At push back the wheel chocks were lodged in place and unable to be moved with both engines running. The push crew advised that we needed to shut an engine down to free the chocks. I asked for Maintenance on the interphone and a MX person answered on the tug comm. I advised that shutting down may cause the same galley problem and might result in a gate return a second time. Maintenance understood and recommended the Engine 2 shut down; to free the chocks; so Engine 2 was shut down. With the chocks free the push continued with Engine 1 running which resulted in the same situation of loss of electrical aft of the cockpit. The push was stopped at my request and the aircraft towed into the gate at XB:22 local with the same MX problem and logbook entry. I notified Dispatch of the return and a waited for further instructions from operations. At XC:00 local I called fatigued for the flight as a departure at this point would have had an arrival time of XD:00 local in ZZZ1 and I was not safe to operate the far into the red eye period. I was never informed that all the failures might be normal and associated with the APU inop and single engine start. If so I would have continued with the normal operation and chock the situation up to my failure to recognize the associated failures.