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!

I would have loved to add these to v1.0 but each feature adds more time and testing, so these will included in v1.1:

• Add an Auto Record button so you can move the Selectors and keyframe automatically
• The ability to bake shape keys, so it will apply all of the current shape keys values and remove all of the shape keys, and the model will retain all of the shape key changes
• Custom import settings for ARKit shapes. The addon will detect if the model has ARKit shapes and automatically divide them up into different sections and categories
• The ability to set custom frame holds for your animations. With one click, you'll be able to set your whole animation to be on 2s/3s or 4s, allowing you to get the Spider-Verse style choppy animation

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.