I just discovered that if you Delete the Memphis Docs plugin after import to WP Docs, that it deletes the mdocs directory and ALL the files. WP Docs pointers are still there but no files exist. You should show a warning that all imported files will get deleted.
Also, if you Deactivate Memphis Docs on the main multisite it gets rid of the Import option in WP Docs, even if it is Activated on the subsite. The import option is not shown. I discovered this when a subsite could not download PDF files in the Media Library after WP Docs was installed.
The option to Import from Memphis Docs has issues in a WordPress Multisite Network installation.