Custom hair doesn't sit right on head in-game?

Hi. The hair is meant to be assigned to the head bone. Right now a portion of it is assigned to b__R_Ring0__.
- delete all vertex groups;
- create a new one with + button, double-click to rename it to b__Head__ ( copy-paste the name, it must be identical);
- select the whole mesh with A, click on Assign.
(ignore the second half of the pic)


There are other problems.
See how a portion of your hair is black? That is because the mesh has multiple uv maps that serve the same purpose instead of one. In ts4 only one uv map can be used to project textures, the second one is for morphing. Speaking of which, you do not have a proper map for morphing and the mesh is vertex painted with the color that is no longer used ( the blue one).

I think a better idea would be to re-do this. Start by re-doing the textures so that all of them fit in the space meant for hair. Then you can combine uv maps into one and re-arrange them. And then do everything else