There is a hat bodygroup if you want to take off the extra hat, but as for the cheek lighting nobody here is sure how to remedy it.

1. Thats why the hat has a bodygroup too.
1.5 Marx's lazerface wasn't rigged to the skeleton at first, so the tie had to be detached from the bones.
2. Valve handles materials differently. The seams cannot be prevented and is due to texture differences. If It wasnt to have a seam, transparent bits would be white. The models that have seams regardless are because they weren't meant to be view as close as you have them

So while I was messing around with this model in Milkshape 3d, I realized the vertices containing the cheek textures needed to be welded before it would look seamless. So there, I found that problem. Maybe the creator will patch this remedy (unwelded vertices) soon enough?

引用自 snugnu：

So while I was messing around with this model in Milkshape 3d, I realized the vertices containing the cheek textures needed to be welded before it would look seamless. So there, I found that problem. Maybe the creator will patch this remedy (unwelded vertices) soon enough?

What do you mean "welded"? And are you sure that would work in/for SFM?