Clothing weights/vertex broken [Solved]

I had my accessory turtleneck working. Alas, I decided to edit the mesh further. I used the mirroring modifier since I'd gotten it to work before I assumed I could do it again. I can't.
The neck and mirrored sleeve (modifier applied) are both floating/attached to the side of her face.

S4S 3.0.1.5/Blender 2.78c

I've run through the tutorials and redone the weighing a few times to the same result. What am I missing?

Blend file
Package File

Thanks, I never would have gotten this far without the resources on this forum.