It's not a matter of

'unlocking' them and simply copy pasting them all on the races.

Au'ra have horns.
Miqo'te have ears
Elezen have ears


They all need to be shaped around the different sized heads which pretty much means making them from scratch

Then there is the decision behind hiding it/showing what to peek out for different helmet skeletons.

We've got a lot of neat hairstyles and they all come at a good rate.