@Steve Dennis Thank you for reaching out to us, researched on your above ask, looks like in addition to the AIP Label, the docs also have RMS Templates applied as part of the Label. Removing Labels are too big of a deal, but Rights Management is much more difficult without access to the Org that applied the Rights Management, in my view first option is good to go with "Ensure that the originating organization identify, remove and remigrate the document libraries and files"
However if you need more guidance, just open an advisory case with our support team on the same, if you don't have a support plan, let me know I can have free support option enabled for you on your Azure subscription for this issue.
Let me know if you have any further questions, feel free to post back.
Please remember to "Accept Answer" if answer helped, so that others in the community facing similar issues can easily find the solution.