I would check the resistance of the sensors at the connectors with a DVOM. You can inspect for any corrosion or frayed wires at the same time. I believe the 2 white or gray wires on the sensor are the heater circuit. I'm sure you can find what the actual resistance values should be online.
Do the O2 graphs look okay?
Both excellent ideas. I would assume the O2 graphs are fine, the heater codes are the only stored faults. I can check though.
I don't think the post-cat sensors should effect how the engine runs at all but it might make me feel better if they're new.
And good call checking RockAuto, with the forum member discount it actually comes out just barely cheaper than Amazon for an OEM sensor.
I am a lazy man and have a good mechanic so I'll probably just have him throw the new sensors in if I replace them. It can wait until the next oil change/tire rotation. I appreciate the links to the Lisle tools though, I may have to pick those up for future use. Looks like the perfect tools for the job.
Thanks for that link referencing the heater resistance too. I may throw the new sensor I already have on my multimeter just to see if it matches that 5 ohm spec.