Honestly not mentioning the males/females is a good thing. That means that no random erradication happened to them and that society itself don't see Viera and Hrothgar as a dying soon-to-be-extinct race. Not only that but tecnically what we see on the first does not count. We, the player, create a Viera or a Hrothgar, not a Viis or a Ronso. If male Viera and female Hrothgar are to be mentioned at all, it should be at the source, no? We have yet to go to "Vieraland" at the source, as well as having a meeting with Fran, Queen Ashe and the resistance. I feel like then it would be the perfect moment to introduce the males, and I kinda feel like this is what SE is planning to do as well.