To those doubting the possibility of this DLC being a "Zookeeper's Collection Pack" now that Zookeeper Day has passed, I think we should recognize that that particular name was given to such a hypothetical pack by the community, and this could still be a pack of multiple (mostly) unrelated animals, just with a different name like an "Around the World Animal Pack" or a "Finale Animal Pack" (although I will admit, those don't have the same ring to them as Zookeeper's Collection).
The presence of enrichment items and a zookeeper on the key art is still making me doubt this is simply a Highlands or Mountains Pack.