It sounds like you would need separate folders for each account, with each being shared with the artists who need to work on them. As long as the source account is active the assets will be accessible. See Collaborate and share CC Libraries with your team in this document.
Also here: Collaborate on folders and libraries from Creative Cloud account
If an account is deactivated the behavior for Enterprise accounts is as follows. You won't have the same options to access assets for Creative Cloud for Teams as this uses Adobe ID which is owned by the end user and cannot be accessed by the admin.
Manage storage in Adobe Creative Cloud for enterprise deployments
"When users are removed from a product configuration, they lose the entitlement from that product configuration. The storage allocation is immediately revised. If users' storage exceeds the revised allocation, they cannot add new files, but they still have access to their existing files. Users need to delete files to free up space and get below their new storage allocation.
However, if a user is deleted, the files on the Creative Cloud storage are deleted and there is no way to recover them.
If Enterprise or Federated ID users are removed from product configurations that entitles them to storage and services, they are no longer entitled to storage. The files are available for 90 days, during which time users can download them. Uploading files is, however, not allowed, and the files may not be accessible after 90 days."
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