Okay, so... I tried multiple versions of the scene with multiple character... and they all have some basic expressive changes, regardless of head mod.
If you are comparing it to the animation posted by RHL:
twitter - https://twitter.com/RHL_90 - SD & MP4 - fanbox - https://rhl.fanbox.cc/posts/7117330 gumroad - https://rhl99.gumroad.com/l/f
www.pixiv.net
there does seem to be some missing eye opening and closing at certain key moments, for sure. However... I don't seem to be able to see an Interpolable entered for that. There are eyebrows, canines, teeth, and tears, but no blinking. Random blinking can be turned on by going into Blend Shapes, resetting the eyes or all and then enabling it under Kinematics.
Of course, I don't really know what I'm talking about so anyone feel free to correct me.