Interspecies enrichment has always been a “wow, that’s neat!” to me rather than a complete necessity. Many zoos in real life house animals of different varieties together and many of those realistic combinations are not found in Planet Zoo’s arbitrary listings. One that comes to mind is Asian Elephants and African Elephants, which would probably make the most sense as higher intelligence animals would sense the need to interact more with those of a different variety. Welfare on or off, there’s still a ton more combinations you can mix together to create unique exhibit dynamics. In my Riverbend Discovery Center I mixed Pronghorn and Ostrich, which wouldn’t be a thing you would see as interspecies enrichment but nonetheless it’s a combo that seems realistic for a zoo to do. The game is all about having fun with what you want to do, and that’s something i hope more people learn with Planet Zoo - the fact that the requirements only serve as a guideline but you can stray from that with no real penalty depending on how you stray. For example, if you use the wrong foliage you only lose 2% at most for overall welfare.