You are a life saver, thank you! This is a completely different setup from the way I had it. I'll have to kind of learn the ropes over again, but it'll be worth it.
So I shouldn't have any more issues with Animate if I keep my setups nice and neat like this with vector images instead of bitmaps?
You're welcome. It's not so different a setup. The biggest change is nesting all of your head assets into a single symbol. This way you can simply concentrate on your head animations inside of this symbol (lip syncing, blinks, eye movements, etc.) and then on parent timeline, rotate the head using keyframes, tweens and easing.
As bitmaps, totally valid workflow, but just make sure you export each layer so they are cropped tight to the artwork. Bitmaps are best when you are creating an art look involving textures that vectors are not able to do. But since you're creating assets that are flat simple shapes - then vectors will prove easier long term and scaleable. So yeah, vectors win in your case.
Just let me know if you get stuck again. I promise the way I set up your file will increase your productivity in the long run. I even take it a step further and nest the entire character in a Graphic symbol, then inside that have all body parts and then the head which has its assets nested another level down. But as I set it up for you will def help you.