Did they forget to add an NPC?

[MikkoAkure]

I could also point out there are Xaela in the First, like (and admittedly an extremely minor character), Princess Sauldia from Il Mheg, who shows up in Branden's flashbacks to pre-Flood Il Mheg.

The First doesn't have Xaela at all. "Xaela" is a clan of Au Ra that only exists on the Source. The black-scaled Drahn that share the same models are typically just Drahn from noble families. Drahn themselves on the First originate in our world's equivalent of Ishgard and have nothing to do with the Steppe at all.