Hey Y'all & Kyuppin! I could've sworn you could map Custom Objects to the mouth like how you can so the eyes, nose, face, and other various parts of the model. I was wondering if this was never a thing with the mouth or if this is just something I'm not able to do. If you got any answers for me that'd be great thanks!

It should work. The mouth had to be set up in the code weirdly because each mouth is made up of 5 separate sprites. 

Or maybe that's what changed at some point. Attaching an item to the mouth right now will attach it to an empty parent object of the mouth sprites. So the object will still be attached, just not to the individual sprite.