I can't really help but I was looking around & someone on YouTube has like 3 stream archives of working on a Miku Hatsune model that does this. Not a tutorial but they recorded themself making it so if you skim around you might figure things out.(Sorry it's a bit long but you kinda just need to skim around while checking the preview when you move your mouse around on the loading bar)

Just kinda know you need certain parts you want to move a little to be their own layer. So you can see the bangs, side bangs, ears & a little bit of hair on the shoulders move, those are their own layer.(Though bangs & side bangs are together from the looks of it)