Apologies, should have linked to @lookmumnocomputer’s Patreon post where he’s building a new Kosmo face to replace the old one (see the Modern Gas video to learn what happened to that guy).
(I’ll leave it to @lookmumnocomputer to decide if he wants to publish these STLs also for non-Patreons, or post them to Thingiverse or something.) EDIT: The STL files can be found via this page.
As for controlling things, I’ll probably just use some simple 555 CV-to-servo controllers for now (if I could only find them).