Update…
The good news; it appears Qobuz just updated my library to reflect the proper added dates.
The bad news; since the old unavailable titles were automatically deleted, replacements lost all tags and edits, and the added dates were corrected, I have no hope of identifying which titles were replaced so that I can add back my tags and edits. This means when I search by tag, these “updated” versions will be missing from my search results, essentially orphaning them in my library. This makes integration with Roon MUCH less useful for me. 
At least with the way it was before this mess, I could see which titles were updated to new versions and transfer my tags and edits.
If it was a choice between accurate added dates and being able to keep my tags/edits in order, I’d give up the accurate added dates since I often search my library via tags. Of course ideally Roon would automatically transfer any tags/edits to the new versions, though I’m not holding my breath for that to happen.
Sigh….
PS - I submitted a feature request