The dev has posted some hairstyle change attempts on discord in the past. Unfortunately, a lot of the characters' looks are tied to their hair, and some look like entirely new characters when it gets changed. So I would not expect it too often.
One reason it works for Sarah is because we know she does cosplay and styles her hair for it, so we are conditioned to still recognize her.
I'm not saying it will never happen, just that for many girls it may be too big of a change to easily incorporate.