"Until now" does not answer why a ton of them would be in Eorzea without a single one being known to travel or have any home anywhere in Eorzea nor even previously seen before. Another player character's race is does not change from another player's perspective. That is just silly. Lore adds immersion. Removing it destroys immersion. I've seen other universes do this too often, and it destroys the immersion enough to the point that it makes unsalvagable. Final Fantasy puts a huge emphasis on story. It is the biggest selling point. Without that, this is just another grneric mmo.

Here is a real question. Why is is so important that this gender of this race be introduced as a pc? Odds are they would not be as feminine as the male miqo'te, given how they live. If people want a miqo'te with bunny ears, they would likely be disappointed. If they were as savage as lore describes them, they would be a real great addition as a pc in terms of masculinity, but they still won't fit lore.