Hopefully it's not too big of an error, just make sure to read the documentation and that all of your shape keys and cameras are labelled correctly. Follow the Quick Start Guide step by step and hopefully the problem won't happen again. If it does, then you can fill out this Google Form and it'll help me fix the problem!

Yes! All you would have to do is disable/hide the head/face bones for your character, and then start creating shape keys for your different expressions. Then you would be able to create the Shape Key Images in your scene and control the character's face using the Selectors and then you can move your character using the traditional rig!

I've tested it on multiple versions, and it works as far back as Blender 3.0 but it was developed and most of the testing was done using Blender 3.6.