FFXIV 2nd expansion: Viera-like race still a possibility?

[Ashewalker]

Another possible route is to have them be a part of Garlemald's currently invading forces. Perhaps the resistance of Ala Mhigo, the Domans, or the WoL's efforts help them to free themselves.

I would say something else...

Maybe... due to Garlemald invading forces, they actualy find the land of Vieras and conquer it, making the Vieras spread through the realm to look for a home, just to survive.