Custom Assets - I believe this is very much possible, by importing assets into the editor.
As far as dedicated servers and playing NWN2 style. Would be cool, but I really doubt the game is set up for that kind of thing. Maybe it is something they can integrate down the road, perhaps for other games, since they intend to reuse the engine. Might not be that difficult to make the editor live or at least add some DM abilities.
