For those interested in an update...
Two days after my last post, I was having misfire issues just going to get coffee Saturday morning. I ended up at the Nissan dealership I mentioned earlier, looking at a 2018 LT1. $22k, just under 6k miles. It seemed to have been taken care of very well, still having the protective film on the touch screen.
I knew the repair to the 2012 could be $500...could be $1,500...and that might not even resolve it. I knew I wanted something reliable, that if I had to run someone to the hospital, that wouldn't be the one time in 3 months that I get a CEL and limp mode. So I made the deal, and even got a new set of snow tires installed for $325 (in additional to the stock all seasons). I checked out my 2012's dash cam after the fact, in setting it up for the new car, and I caught a recording of the used car tec running the codes and talking on speaker phone with his boss. It sounds like they felt the same thing, that it was related to the 5th fuel injector, and it could be a relatively minor fix or a pricey fix, but that it's "not the end of the world".
I haven't gotten used to the turbo 4...I miss the low end power at parking lot speeds with the v6, and power delivery is very...peaky...but the car is still fun. What really struck me is how well it handles, feeling much more nimble than the 2012.
If anyone is interested...they listed my old 2012, I'm assuming they resolved the misfire issue.
https://www.nissan37.com/auto/used-2...r-nj/42707952/