Gen 2 shuddering and throwing misfire codes.. could use some help

I’m sure others on the forum with much more experience will have specific tips on the implications of the codes and the subcodes but in the interim I’d download the service history on the car from Toyota for free or get a carfax report to see what’s been done with it if they used a dealer or other retail mechanic.

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It may be that those are the original plugs. If so, misfires at about 200k miles would not be surprising. I think you're starting in the right direction.

It could also be dirty fuel injectors.

 

Problem with chasing misfires on this car is the factory denso coils are expensive at $100 each. But they work. The parts store cops suck for $50 each. So throwing good cops at it gets expensive.

Unfortunately rolling misfires are sometimes caused by blown engine rings or bearings gone. People tend to never check the oil in a Prius and they start eating oil so by the time the check engine light comes on to tell you engine is dry its too late.
Really common on this site. Nobody checks there oil especially if they get the oil changed at the dealer.

Pull the plugs see if there's oil on them. That's pretty telling If so if it was me I would do a compression test on all 4 cylinders.
In fact I would do a compression test first before spending a dime on this car.

Could be cat is clogged up but that's caused by bad oil eating.

And 12.5 volts at the front jump point is just about perfect. A perfect 12 volt in a G2 lives at 12.6 volts at the jump point.

 

Personally, I would clean the MAF first -- it's easy enough. And, as suggested, pull the plugs and see what they look like. But, my daughter's car had the pretty much the same issue -- except we did not pull any codes -- and cleaning the MAF made it all go away.