With the limited info here there isn't much to nail down a good cause. I think a lot of possibilities would be pretty rare to have happen...not impossible. Hacking...no as further stated below. If we look at all the failures as having the same root cause, then maybe a bad/loose ground on the main computer or some other failure on the main computer...maybe a corrupt software load.
Looking at the failures individually... Temporary(because you said it resolved itself in your OP) GPS failure(due to valet situation) could just be because of being in a parking garage and GPS receivers/software can have issues coming back when they have lost GPS for a time period. GPS almanac/ephemeris data update cycle coinciding with loss of GPS in a parking garage could compound the recovery issue a bit.
Secondary phone not connecting(temporary as you stated)...I've had that issue, I've had the primary phone not connect sometimes too...this could just be a protocol timing issue between the phone and car.
Voice commands not working(temporary as you stated). This is generally due to loss of internet access...similar to GPS, if a cellular device loses signal there is a process for how it behaves and searches. At some point, the device may give up and "take a nap" for a while and then try again later(or not which would require a power cycle). Could also be a software glitch.
Damaged camera cover...what camera cover? and I hope you are not trying to insinuate that this is how a hacker would have gotten into the system...
Passenger door handle not presenting(temporary as you stated)...sensor just didn't happen to sense a touch due to dry skin, glove....RF geometry issue between keyfob and receiver in car....
Rear hatch not closing...I don't know anything about this....motor failure, software glitch, power/ground issue...
Now for some mics comments...
All these failures in a 12 day window? Something bigger is askew.
Sure maybe...but not hacking...I don't know why you are trying to make that jump I mean if you were that paranoid you would never have given your car to a valet... Sure there could be a bigger failure that is causing these issues but thinking hacking is a bit of a stretch...without there being a reason to specifically target you personally.
Because it has all happened in a 12 day window, with the failures beginning immediately when we picked the car up from the valet.
Again, bigger failure linking everything could definitely cause multiple failures in rapid succession, but I would be more receptive to you thinking it is an acute main computer failure than hacking by the....valet....again unless you think there is a reason to specifically target you personally....but then back to you wouldn't have left your car with a valet in the first place.
Rear hatch and GPS should be easy to demonstrate with a video. If these are intermittent and the SC can't reproduce, video could get the SC working on it. Good all other problems are resolved.
This.