Hi - Posted this before but didn't get a reply - (I'd really appreciate if someone might be able to help me).

In a workflow using autorigging - where does the facial animation come in. I'm used to setting up blendshapes in maya prior to skinning. Is there a houdini equivalent? How do I apply facial animation to my character?

Take a look at the Toon Character. If you dive into it and go into the toon_character_deform_rig/skin/ you'll see how all its blend shapes are setup.

you can also do morphs or as maya call blend shapes in houdini.
or you can set up some null that can aid you setting up expressions in the face.