Plex Pass will enable some extended functionality in the Dashboard. Among those, a full playback history.
That being said, running Tautulli additionally, will provide you with more detail info.
No.
Can I select which libraries are shown on their Plex Client App?
Yes. You can even determine which content rating a user is allowed to access.
See https://support.plex.tv/articles/204234313-example-plex-home-setup/ and https://support.plex.tv/articles/204232573-restricting-the-shares/ for more details
can I give a custom name to each account/member by MAC address?
No. You can only see the Plex account name/email address.
On ‘managed users’ you can set the user’s name yourself.
Devices are connected to user accounts.
You share with ‘user accounts’, not with ‘devices’.
This would also be nice for example in tracking the usage for each of my kids.
Both the Dashboard and Tautulli will enable you to do that.
