List existing file server permission groups/users

Solution 1:

you have several options. But first I would suggest you maybe make your life easier by using xcopy to only copy the directories and their respective ACL/Auditing settings.

you might be able to continue with cacls or use something else...

1. AccessEnum from Sysinternals
2. PowerShell may have some possibilites. This LINK may help (corrected).
3. Python calling on Win32 API. I haven't tested this LINK, but have a look...

All that, but why not do the human part and sit down with people and ask who needs access to what? Then create a new structure and permissions based on the needs using your conventions and documentation.