EG:First question comes too mind,how easy is it too create prc race/class npcs/villains etc?
The races work ok for the most part, but a lot of the PRC class features don't work. The stock NWN AI will fire the PRC spells & psionics, but poorly & with no augmentation. Custom AIs such as TonyK's & Jasperre's ignore the PRC completely.
You can make NPCs with PRC classes in the toolset, but they won't automatically get their class features since most of them do not have advancement packages associated with them. They will get their racial features but won't use anything that has to be activated (i.e. githyanki's Blur ability). PRC casting classes (like the archivist) can't get spells at all.