Further study suggests that case #3, above, may be a successful, rather than failed, sync. I think I may have incorrectly extrapolated from the "Catastrophic" error. I was expecting a successful sync operation to pop up or display a message of some sort. But I now see that it doesn't. So I'm not positive the related syncs were successful but, for now, thatt seems the proper assumption.
With respect to case #2, I haven't been able to reproduce the "Catastrophic" error. But, if I figure out how to reproduce it, I'll capture and submit the proper debug information.
Thanks again for your help.