Dealership Problem

If I'm correct in understanding that the car has a 100,000 mile powertrain warranty? The car only has 23,000 miles on it now? That leaves 77,000 miles for the problem, if any to rear its ugly head. You have documentation already. Continue servicing it as you have, with the same dealer if there hasn't been any issues if you feel comfortable enough to do so. If not continue with another dealer so independant shops can't be blamed for causing it.
Does she really plan on keeping the car for 100k miles, or will she trade it in before that? If there's damage you'll see a problem long before 100k. After that it would probably **** the bed on its own anyway. So if she's not gonna drive it that long don't lose sleep over it if it aint smoking or knocking.
IMO it sounds like they did a little CYA about the o-ring failure. But honestly, I don't see where they ducked any responsibility beyond that. I don't think there are many techs that wouldn't try to CYA if the same thing happened to them out there. Mistakes do happen. If they cover it (under warranty) IF there's ever a problem then that's the best you can ask for. If not then start making calls. As long as you have the invoice form both visits & they should be dated w/ mileage then you have enough documentation.
I've been in the business over 30 years. Starting a big **** storm over it, as some suggest at this point isn't going to do anything but risk a bad relationship between you, the dealer & possibly you & the factory(in this case Dodge, or Fiat or who ever owns them next if there is a problem down the road). You're gonna need them both if there is ever a problem. I wouldn't expect them to cover anything beyond 100,000 miles on it though.
The good news is there had to be enough oil in it to get as far as she did before the low oil light & oil pressure lights came on(20+ miles). So even though it was leaking she still had some oil pressure in it, so there may not be any damage.

I hope it is ok & she has many miles of happy motoring left in it. Good luck.