Hello again.
Thanks for your input. After reading your "Getting Started" posting, I realized I have been using the PluginMgr and Plugin Extras incorrectly. This time I selected the test photos after making my metadata selections in PluginMgr and then went to PluginExtras following your instructions. This worked and the "rc Standard" metadata did show! Thinking I had achieved a successful completion I closed Lightroom without recommitting or viewing the log file. When I re-opened Lr metadata had reverted to default and rc Standard selections were long gone and the plugin was disabled. So, I updated ExifMeta to v5.8 and started again—
I have attached a PDF with the log (showing screen grabs and logged errors). I spent some time getting familiar with the log contents to get an understanding of things to look for in the future (a major firmware upgrade to my camera this month—oh boy!). I've also attached the diagnostic log. Maybe they will shed some light on this issue.
Again, thanks for your time, patience, and help!
SCC