I wasn't able to fix it, my knowledge in blender is shit x-x But to me it seems like the eyes are looking at the ears by default, which makes them look up u-u
The avatar is missing some DynamicBone scripts. it's easily fixable if you have the DynamicBone files, just extract them into the unity project.Other than that, I got the same problem with eyes as rohart. I'm going to see if I can fix it myself