The way I've set up the rig is as follows:
[main BONE layer] main rig controls and bones are here.
....[SWITCH layer] between closed and open mouth rig
.........[SWITCH closed mouth shapes] - this moves with the whole rig just fine
................................m, n,


.........[BONE layer open mouth shapes (mask)] - this bone layer has bone dials to alter each inner mouth shape to turn the inside 3/4 view, and to make each frame smile/frown more.
...................teeth
...................tongue
...................[SWITCH layer of mouth shapes, different sizes and sounds]
................................a, aa, aaa, e, ee, ee... etc.
Would this only work if I have the bones for the lip sync rig set up in the main bone layer? I chose to do it on the inner layer so I could transfer the lip sync rig onto different characters/angles without redoing anything. Now I'm worried I'll have to redo every smart dial action to move it!
Is there a way to parent all of the bones in this nested bone rig to the main one?
I'm also having an issue with this rig where when I set up an eye to blink with a bone dial on the main bone layer, it stops the bone assigned to controlling the pupil for that eye from working, even though the action doesn't use the pupil's layer. Though the eye is contained as a group for ease of setting up other actions. Not sure if this is related.
Here's a render of the issue, you can see the closed mouth moves with the head and not the open one. Also for some reason, the outline disappears from the open mouth in the render even though the mask is set to 'exclude strokes' and displays perfectly fine in the viewport. I tried 'expand mask by a pixel' and no luck.

Thanks for reading all my weird Moho issues, if anything was unclear or you need more info to help, please let me know!