I don't see anything that looks like dry rot or a structural issue, but based on what you've said here, I would replace them. I had a set of those that were on our minivan when we bought it. We got stuck in a couple inches of slush turning around on the test drive. I replaced them as soon as I got it home. Those tires, like many othre Michelin and Continental tires are made with 2 different rubber compounds in the tread. The outer half of the tread is a soft compound with good traction on ice and snow. The bottom half of the tread, where those are now, is a harder compound with better wear characteristics, but lousy ice & snow traction. Pretty much anytime you see tires that get good ratings for ice &snow traction and treadwear warranty over 60k, that's how they managed it. Rubber compounds soft enough to grip on ice in cold temperatures are just too soft to hold up for 80k miles in the summer heat.You've touched on some other points I didn't mention and yes, parked outside rain or shine.
1 - Daughters vehicle so a little more concerned.
2 - Drives 70 miles per day round trip for work which I would consider substantial.
3 - In NJ so weather can be an issue during winter months.