request/suggestions for best Drobo setup in mixed environment of OSX, Win7 and VPN

Hi All,

Our Use Case:
We currently have an Apple Server with Airport Extreme but I wouldn’t mind eliminating the Apple Server as its mostly not used and is a bit of a headache and I am not able to connect with our 2 windows laptops which is really inconvenient.

We are an office of 5-8 people that use both Windows and Mac computers (mostly Mac). I don’t expect to expand much beyond 8-10 people any time soon. There are are also two Apple Video edit systems as well but I back those systems up separately.

That said…

[]Can a Drobo NAS replace our Apple server and easily manage file access remotely to both Windows and OSX? This does not need to be really robust. VPN is occasional.
]Can Drobo work with our Airport Extreme for VPN or can Drobo manage that?
[]Can Drobo work with both Windows and OSX in a shared environment so files can be shared. The only permissions I really need are group access and remote access. Nothing fancy.
]I was thinking about the Drobo 20TB (5 x 4TB) 5N 5-Bay NAS?