In a French thread asking about male Miqo'tes, a community rep popped in to note basically only that she is Roegadyn.
Still begs the question if they'll be playable or NPCs only, but at least we know there will be some explanation about the other genders of these races.
Hopefully the game explains where all the female highlanders are too.
Kamalon, an SE community rep wrote:
Je ne sais pas si tout le monde l'avait remarqué, mais Merlwyb Bloefhiswyn de la grande compagnie du Maelstrom est bien une Roegadyne