For the benefit of anyone following this...a big Kudos to A Howard for getting this resolved and it's not the first time he has rescued me from my own ineptness.
So the reason "This item is not locally available" is because after initial scan to catalog, I consolidated folders of scanned photos into one folder (simply named "scans"). I did this in the macOS Finder so the PM+ database was not seeing those files where they were expected. This was resolved by "updating folder paths" for those files.
In hindsight, I am somewhat surprised that a FULL "Catalog Sync" didn't resolve that, but maybe I moved the files AFTER the sync. If anyone knows if that would have resolved it, please let me know.
Thanks again...gary