Since Hrothgar have hairstyles tied to their character creation options rather than being separately selectable, you will not be able to apply unlockable hairstyles, but they might implement more face types after 5.0. As for Viera, there's some legacy haristyles they'll able to eventually implement, but not all of them. Some of unlockable hairstyles should be supported, others may not be.
https://www.reddit.com/r/ffxiv/comme...shida_summary/
Interesting instead of more hairstyles for Hrothgar, they might possibily get more face options then the other races with possibly two hair styles attached. (I'm assuming since that is how the other faces are with hairstyles)