I want to make a point on this. I don't know if anyone has brought this up yet. BUT at what point have the Lupin been identified as a beastman tribe? They have not at any point in game been said to be one. It is assumption that they are one and there is actual proof they are not one. If they were a beastman tribe. The Garlean empire would not have conscripted them.
As far as the Viera are concerned. we might see them in the 24 man raid.
This might be the solution that SE plans to add. female Viera and male Lupin as new the race in a later patch.