I'm following the new video tutorials, nice stuff!
When I create the Proxy geometry, I notice that the setting for Show: Bounding Geometry or Proxy Groups is important when you save the geometry, i.e. what you see is what gets saved. Easily fixed if you make a boo boo (like I did) but you might want to either highlight this in the video or (better) check the setting and ask if the user really wants to save the Bounding Geo instead of the Proxy Groups.
Once the Anim rig is created there is a jaw control, yet when creating the Proxy Groups, there is no way to specify what geometry is attached to the jaw, so animating the jaw control shows you nothing

Speaking of bugs, the super-annoying bug where selecting (using Pose or Select/ERT) an Unlocked HDA jumps you inside the HDA is still there! Is this going to be fixed soon? It's really disconcerting and I can only image baffling to new users.
EDIT: Any news on the auto-tab switching being fixed? I find that crucial to working with a complex anim rig like this (or the Toon Character).
EDIT: So, in the paint weight tutorial you either have to have a colour already on the skin and use MMB to select it, or choose from the insanely long list which muscle you want. How do you just click on the bone/muscles in the UI like you did in H8? That seems the easiest, fastest and most intuitive way of doing it, I have to assume that's possible in H9

Cheers,
Peter B