jhustead:

I'm using Mimic 3 Pro for Poser.  It's a standalone application, rather than a plugin.  The Lightwave plugin is sold separately.

Mimic automatically generates gestures (head movement, eye tracking, blinking, and brow motion), unless you disable those options.  Gestures are apparently randomised ... if I run the same sound clip through the session manager repeatedly, I get different results each time.