How can face PARTS (ear, nose, mouth, etc.) be extracted for modification?

[FastestDogInTheDistrict]

If I wish to edit meshes for noses, ears, etc., how do I get the data?? How are the files unpacked so the meshes can be tinkered with (note: no, not BSA unpacker. It doesn't unpack this data, just the files which seem to either contain or reference it)? I can find information that seems to talk around the outer edges of this, but not information on how to accomplish it.