The model appears to be correctly skin wrapped, but there are some areas that will require some troubleshooting. It's almost there, all player modelers have experienced these kind of errors, sometimes you forget a few verts and most of the time you need to tweak the weight distribution for better movement.
To catch verts left behind, you need to rotate the bones and you will see those stray verts "stick" into place while the rest of the mesh follows the bones correctly. Dont forget to turn on angle snap and ALWAYS put bones back into their original position.
Another way to catch the verts is by looking at the color of the weights, whenever you see a blue section it means very low value or no weights. I strongly recommend following the skin modifier tutorial to understand how things work:
Since the clothing is not skin tight like the source mesh so not everything was "caught" by skinwrapper. Go back and manually weight these areas, the sleeves are the first obvious meshes. There's no way around this, tweaking will always be involved when the mesh is different from the source.
Meshes that needs weight:
-Hair styles: some unweigthed verts at the back
-Under the chin of the "head mesh"
-l_arm and r_arm (the hanging part needs weights)
-Finger tips on both hands need weights (you can reuse the hands from the sdk file if you want, if you do, rename them correctly)
I suspect the hips_belt mesh will need some adjustment, as of now it's weighted as a "stiff mesh" but the lower part of the torso has some movement into it.
For some reason the head was not linked to the torso, the extra hair styles appear to be linked correctly to the head but the head itself was not linked to the torso.