02-01-2012, 03:10 PM
Here's the deal.
The reason it's a bad idea to use a server as a workstation is because the default user type is Admin.
In the old days (Snow Leopard and older) The "server " OS was it's own animal. Software was not supported for the server OS. You might not have desirable results installing and running CS5 on Snow Leopard server.
That said, Apple has turned the server OS into more of an Application or group of applications and services. Which leads me to believe that the software support for third party apps might be a better fit.
As for drive space, you can create custom shares and put them anywhere you want on the server. Macintosh HD or Server HD, doesn't matter. They give you two drives simply to have more storage, or in the event you would want to configure redundancy with a RAID1 drive scenario.
Since you only have four users you most likely don't want to bother with Open Directory and network accounts. And for the sake of simplicity you might just create a generic user that is used for connecting to the share. Since the local user of the Mini won't need to "connect" to it you may just create the two local users on the server and call it done.
Local login account would be something like Joe Smith and the network shared account might be Server.