Report w/ Unassigned "floating" Cost Center Hierarchies

I've been attempting to write a report in Workday that ought to be simple: extract all cost center hierarchy values in the system, independent of cost centers assigned to those hierarchies. The purpose of the report is ongoing FDM clean-up/maintenance monitoring. We're trying to find all past cost center hierarchy values that were created in error or no longer have any cost center values assigned to them so we can clean them up. These are what we call "floating" cost center hierarchy values - they exist in name, but have no superior hierarchies, no children, no cost centers assigned, nothing. Which seems to make it impossible to extract them from the system or even locate them in Workday as there's no security assigned to just these floating hierarchy values with no company/cost center/etc.

Thoughts? Is it simply impossible to extract these "floating" cost center values only from Workday on account of not having any security assigned to them, thus kinda "ghosts" in our system? I get why this is tricky in Workday, but is there really no way to extract simple hierarchy values for FDM maintenance from the system? That seems very....silly?

Note: We have existing cost center reports of course that have the hierarchy values on it for those cost centers, but that doesn't work for this purpose as we're chiefly seeking to find all the cc hierarchy values that have NO cost centers assigned.