Oh yeah, perfectly safe to drive.

Likely to have less fuel mileage.

But if your engine feels like it’s misfire, it’s probably best to park it and change those sensors. Easy job, get an o2 wrench or socket, and swap those bad boys out.

Yes, it’s going to run different though.

You don’t need 4 sensors. It’s not possible all of them died at once. This is an electrical issue. I would start with checking the oxygen sensors fuses.

Yep, but you have an electrical issue with the O2 sensor heater circuit. Read rule 8 please…