Is there a feature that enables the production of faces on wood to be used as part of a puppet show? For example uploading a jpeg of someones face and being able to modify the z tool path to cut various depths for a face?
It sounds like you want Photo Carving?
(this would be a nice plug in 
)
In the meant time for your application there are various Photo Carve apps that can do this.
PicEngrave makes one
Vectric as well one (you may need a different post processor to make it work)
These are all 2D though. Kind of like half tone printing. SO the marionettes would have flat faces (or possibly back lit litho pane faces.)
Fantastic Aaron thank you for your help
PicEngrave can spindle carve a photo in 2D, 2.5D & 3D depending on how the image is edited & the settings used.