What's the best way to manage users and access?

I’ve selected the plugin Membership 2 Pro but that’s only because it’s the closest I can come up with,

I’m after a staff management solution for a local network intranet, but it will more than likely end up on the internet as well. It’s more about having control over who has access to what (admins, supervisors, posters/editors, other staff (ie won’t/can’t generally post), developers etc etc as well as a guest level on the outside, although that could be a totally separate solution.

Paid membership and gateways are all overkill and unnecessary. But teams and hierarchy are important