@ANoobis
If they do introduce foreign species, they should stay foreign. As much as FiM neglected Zecora’s backstory, that was the one and only time they didn’t end up revealing yet another foreign society that was in Equestria’s backyard all along.
Still, there should have been the rare background zebra (and kirin!) in crowd shots of Manehattan and Canterlot.
Crackpot G5 kirin introduction storyline idea: when the ponies split up, the kirin went back into isolation to avoid the fallout of pony political struggles. Ever since then, they send out explorers every decade or so to see if it’s safe to have contact with ponies again. Their policy is that they won’t reveal their village until ponies have reunified: even if the ponies the exploration party encounter are friendly, they can’t trust segregated ponies to remain peaceful.