I recently visited Oudehands Dierenpark in Rhenen (NL). They have some typical mixed habitats but also a few that caught my attention:
Wolfes with Brown Bears - in a quite spacious forest type enclosure. Three bears were rescues from a Bulgarian bear farm which was closed in the 90s, and they weer doing pretty well. The wolves were just chilling nearby, no issues.
Meerkats in Gorillas enclosure, maybe just temporary? There was no information about it but both species seemed unbothered by each others presence.
Red River Hogs with African Bush Elephants - I think there is even a photo of this enclosure in this thread. Still, quite unusual mix, isn't it?
A more typical Red Panda with Reeves Muntjac - the only thing that surprised me was how exposed those (shy) animals were. I think they should have more hiding places. Muntjacs seemed quite stressed to me. They live just next to the Giant Panda house so it's usually quite crowded area of the zoo.
Another example is from a different zoo, Burgers Zoo in Arnhem. They have a mixed habitat for Collared Peccary and Prairie Dogs. They seemed quite happy, maybe the peccary in the game should also have an interspecies bonus with the prairie dogs?