In the attached images, I have a mesh that I rigged with automatic weights. The auto-weight turned out pretty good, minus a few tweaks. However I ran into issues with the mouth and eyes.
I applied weights to the teeth and eyes based on the weights of the nearest vertex, or based on what was half weight-painted (auto weight got the top eye-lids and not the bottom, same with some mouth meshes).
After testing the head movement, I noticed the bottom gumline of the teeth doesn't move with the rest of the mouth, despite having the same vertex weights, Same is true with the eyebrows and eyelashes. When moving the neck bone I noticed the problem persisted with the bottom gum line but not the eyebrows or eye lashes. As far as I can tell the weight painting is the same on both bones.
The goal is obviously for the eyebrows and eyelashes to move as they do in the neck movement image, and the gumline to stay with it's set of teeth.
I tried separating the meshes and connecting to the head bone (as you would do with hair?), but when the head and neck moved they didn't keep their position on/in the head. Does anyone know how I can fix all this?