TY :D
They are more like programmable avatars. If you right click them, you get the same options as clicking on a real avatar. If you visit the ohn freebies world, SW area, you can see the one i just put out. It's configurable, you can define a long sequence of actions for the NPC to take, in a notecard. It walks, talks, is animated a couple times, sits on objects. With the default appearance, it wears a freebie AO so its walk doesn't have to be the duck walk. You can make an NPC look any way you want by dressing up that way. NPCs can also touch objects, run, fly, shout, whisper, I forget whatelse. You can use listens and radars to script interactivity.
You can take a copy of the package I put out too, its copy/modify/transfer, so you can get the scripts and use elsewhere. This version can also be configured to rez objects on which the NPC can be instructed to sit as part of the action configuration. Out of the box, default configuration has it rez 3 such objects that are used in the course of the action sequence.
ETA: I should also say that these things are done using the standard OSSL NPC functions, so these should be functional on any opensim region where the owner of the controller is the owner of the region.