Stop trying to impose real world concepts on Final Fantasy. Are they supposed to consult wildlife before they use an idea?

I have never seen the word mammal used in game so I have no idea if they consider anything a mammal. Even if they do it's likely not exactly the same concept as we have. The people of this world are collectively referred to as "mankind" especially by the dragons. That suggests, (but is not conclusive) that all the races we have are related.

I'd be fine playing a race that can't wear every mogstation outfit.

the player-base is not monolithic.