I'll lean towards the Bird Strike option causing damage to the wiring.
Pages 4 & 5 on the .PDF Page Count are simple Schematics.
Looks like both engines have Generators and also the Aircraft has an APU (Auxiliary Power Unit) Generator as well. Automatic Power switching will switch to any of these systems if the needs arise.
The easy explanation is the pilots messed up. They had a bird strike that killed engine #1 the First Oofficer who should have been running the bird strike check list messes up twice. First he doesn’t immediately start the APU which would have provided not only 400HZ 115V power for every system but also the third independent hydraulic pressure system AND most importantly high pressure bleed air that is required to start either one of the main engines. So no APU is first critical screwup then he in the panic shuts down the wrong engine 2# this with #1 bein killed by the bird strike and no APU running means they just lost all hydraulics, electrical expect for critical battery back up instruments and also the ability to restart either engine since no high pressure bleed air either. They lacked the speed or altitude to attempt a windmill restart on 2# so they are dead stick at this point flying on back up instruments and manual flight controls. They didn’t drop the RAT the ram air turbine which would have spun up and given basic hydraulics and emergency electric power which they could have then used to start the APU with , and with its high pressure bleed air restart #2 engine. I say the FO panicked and shut down the wrong engine as the first responsibility of the Captain is to fly the aircraft so the FO would have been running the checklist and attempting restarts. Lack of power and hydraulics also explains the lack of flaps they had zero hydraulic pressure to drop them. The gear has gravity drop down back up they missed that in the check list as well. With no RAT and time dead and one inoperative engine plus no APU they were dead stick and yes the black boxes would be dead as well. So the FO killed the good engine by mistake at least 4 min from touch down.