Ed you are correct that the two items are not related.
Good news- I replaced the thermostat earlier today and the code for faulty electric thermostat did not reappear. Took me about an hour and a half, I did not remove the aluminum throttle elbow but if you are going to do it this way you need a good swivel socket set. A hook tool is also handy for prying the lower hose off the tstat. I couldn't find mine so I used a small Allen wrench and vise grips to hook the hose and pull it loose.
Bad news - fluctuating idle still there. I'm going to replace the CCV next.