I figured out the reason the standard head works and the others don't. The default head is part of the armor mesh and is the "no replacement" instance. When you use a different head it removes the standard one and stitches on the new one. It looks like A4 must have had the stitching wrong. Anyhow, this one should have it right, as well as reduced shoulders.
http://ghastley.org/ds/download/Reduced_fg_A4.zip
I figured out the reason the standard head works and the others don't. The default head is part of the armor mesh and is the "no replacement" instance. When you use a different head it removes the standard one and stitches on the new one. It looks like A4 must have had the stitching wrong. Anyhow, this one should have it right, as well as reduced shoulders.