Alpha problems.

So I’ve been working on a minecraft rig for the past few weeks (getting close to about a month now) and I have set up the rig to be compatible with any skin, even skins with helmets. However, one constant problem i’ve been having is that if there is a skin without a helmet, or say that a helmet is a headset, the shadow is persistent and annoying, also note the edges on the rim cleearly outlining the supposedly invisible mesh. example:

How do I fix this problem?

the .blend file is also attatched below.