Qrz

Seems like it. The PC mount can go smaller or larger from what I'm seeing, and they don't know what size case you're using or how far the feet stick out, so their minimum recommended height is likely set to try and avoid people clamping their desk down on their foot because they had a weird case, and getting mad at SecretLabs. 

Why not lock the screen on the workstations? That way no one can access anything on the systems when its locked. Locking just the share doesn't seem like a great idea. At my work, the shares are auto mounted at login, and its all tied to login, for security, your just force a lock screen..

This isn't a FreeNAS issue, it is behaving correctly. Ideally your users lock their computers when they walk away (or you set the screen saver via GPO to lock after xx minutes of inactivity).
 
I think it's a bad design to require them to sign in again vs properly locking the workstation, but if you must you can just create a schedule job on their workstations to: 
net use * /delete
This will drop all network drive connections.
 
Or you can create a cron job on freenas to drop all connections over port 445 ever so often.
 
Your router wasn't behaving properly if people had to keep signing in over and over. This is either because the firewall rule drops a connection configured under timeouts or poorly implemented SMB.

Totally agree.
 
Your CPU is more than capable to do that and the GPU should play at least at medium setting PUBG over 60 fps.
 
The only upgrade I could suggest (not mandatory, as your GPU is decent according to your game visual setting) would be a new GPU. But I repeat myself, not mandatory. Only if you want better visuals and FPS.