Intermittent Display/Control problems

Three intermittent problems with 2012 Prius Two.
1. Backup camera usually doesn't work but sometimes does.
2. Car 3 times has not gone into start when we press brake and power button. All the error lights go on. We keep trying, and eventually, it goes on and the problem does not often recur. The most recent time this was after stopping for a few minutes after hours of driving, so the battery should have been fully charged and everything warm.
After the second problem, the dealer checked it out, said the 12 v battery was fine and couldn't replicate a problem.
3. Just yesterday, with lights and window washers on, only the Ready light, the Gear indicator, and the headlight lamp were on. Everything else on the display was dark. No speed, no gas tank indicator, etc. Turning the headlights off and on fixed the problem for about 5 seconds, and then it recurred. This morning, with no rain and therefore no wipers, there was no problem, with or without the headlights.

Any thoughts or ideas? Just under 36000 miles, and just under 3 years. Not sure how long is warrantee on electronics.

 

Yes - both I and the dealer checked the 12 volt battery.

 

I see the warranty expires in 310 miles. I have an appointment Wednesday. I'll make sure they log the problem, even if they can't replicate it. If it later develops as a more systematic problem, hopefully I can argue the problem existed before warranty expired - just wasn't able to be found and fixed at that time.