Just picked the car up from the mechanic, they replaced the front 02 sensor and all is well. Idles so quiet you can barely hear it running (my other car is a Trans Am...) and no more hunting idle and CEL.
That said, I'm giving it a couple of warmup cycles before breaking out the champagne in case that wasn't the problem, or the only problem.
So far, I have to say I was pleasanty surprised by CarLand (where I bought the car) because they said they'd take care of it, and they did. The car had the CEL when I went to buy it, but they said they'd fix it... and this car had the clutch replaced so I guessed (wrongly) it was maybe related to that - unplugged sensor or something, and I wasn't holding my breath that they'd actually fix it or fix it at no cost to me... this is a used car after all... I was expecting a 30 feet, 30 second type of attitude when I went back on Monday.
Anyway, it looks like my AutoTap wasn't lying to me - the 02 was fubared. I'm just happy I didn't have to pay for it or crawl on my back and do it - the whole point of buying this car was to find a good family winter car that I didn't have to spend a lot of time fixing this winter and had a real back seat. (Neither a 90 Beretta + 2 kids or 90 Chev 1/2 ton regular cab + 2 kids doesn't really work.)
Ray