As a rigger at MPC London, I worked with Andreas Graichen on the hair and facial of Mr cheese. Andrea Falcone made the body.
2 differents rigs were made for the hair. Due to the number of hairs it was build using script (mel).
One rig with straight hair, growing and splitting with square section. Mainly made by myself.
One rig with long hair getting curly with round section. Mainly made by Andreas Graichen.
"Hairs systems" were driving the skeleton for global movement. And when needed, "nlcoth" simulation for contact issues. such as:
Animation => hair system => skeleton => geo => ncloth
Facial rig was very simple and body was build from MPC's home made human and then modificated for the specifics needs.