The requirements to play in the world of Dysotopia are simply a vanilla copy of Neverwinter Nights 2 and all expansions. You can pick up the complete DRM free version at GOG.com for under $20.
Any additional content will be delivered to your game client when you connect to the server for the first time.
You will also have to change your client port if you plan on playing the game with multiple clients behind the same firewall.
It is highly recommended that you install and use Skywing’s NWN2 Client Extension. This will re-enable your server listing feature in the NWN2 client and make it possible for you to connect to servers using the UI.
Characters are tied to your NWN2 registration key (received with a game purchase) as well as with the account information you use to log into the multiplayer portion of the game. Since the game is older, the login services no longer handle authentication so authentication is done with registration keys.