Well, I think I have resolved my problem; don't know if this has anything to do with the others in this thread.
I mentioned in my first post that I did not understand why Fit was so high on the list since I had Activity Tracking turned off. Well, I thought about that some more and - a little bit of background first: I have an LG Watch Urbane with its own built-in step counter. I had been playing with using the Urbane's step counter vs. Google Fit Activity Tracking trying first one and then the other. Frankly, neither impressed me very much but it seemed to me that Fit wasn't ready for prime time and so I disabled Activity Tracking last Friday. Okay, so then why was it still one of the top battery consumers? Not only that, why did my Urbane display a Google Fit card telling me how many steps I had walked when Fit is supposed to be turned off?
I wiped the cache partition (
https://motorola-global-portal.cust...prod_answer_detail/a_id/102414/p/30,6720,9293 ), fully charged the phone and then rebooted it again. Still, when I checked later Google Play Services was at the very top of the list and Fit was the second entry.
So I went to Settings -> Apps -> Fit and tapped Clear data (I didn't care about losing the existing data) and then, just for laughs I also did a Force stop. I rebooted the phone once again.
Now, about 20 hours later, Google Play Services is no longer at the top of the list, Fit is not in the list at all, and my battery life seems to have returned to normal.