While I think many of these are very interesting mixes, I do think some of them would (almost certainly) not work. Obviously a lot of this is entirely dependent on the gender and temperament of the animals in question.
21. Common Warthog, Honey Badger
Eek. Two potentially highly aggressive and highly defensive species in the same exhibit. Don't think this would end well.
1: Hippopotamus, Marabou Stork, Great White Pelican, Yellow-Billed Stork
There is a very similar at ZooParc de Beauval in France, and I agree that this might well work. They don't have the Marabou stork however, and I think this is the species that could potentially cause problems. Luckily I think the other two bird species are large enough to avoid being quick snacks.
2. Blue Gnu, Sable Antelope, Impala, Cattle Egret, Red-Billed Oxpecker
I reckon this could work, although the impala would probably have to be in larger numbers than the other two and the exhibit would have to be completely netted over. It would be nice to have a new Antwerp Buffalo aviary though

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3. Giant Anteater, Greater Rhea, Cocoi Heron
I think this would work as all three are pretty harmless towards each other

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4. Rock Hyrax, Peach-Faced Lovebird, Speckled Mousebird, Long-Tailed Paradise Whydah, Northern Red Bishop, Common Waxbill, Pancake Tortoise, Common Agama
Nice one. Only think is that the viewing opportunities would have to be quite creative to allow the visitors to see all the species without having an exhibit that is too small.
6. Koala, Short-Nosed Echidna, Galah, Blue-Winged Kookaburra, Crested Pigeon,
Kookaburras are essentially a no-no in a mixed exhibit. They aren't really the kindest birds - any puggles or joeys wouldn't last terribly long, nor would any pigeon or galah eggs.
8. Brush-Tailed Rock Wallaby, Superb Lyrebird, Blue-Winged Kookaburra
Again, the kookaburras are the catch.
9. Great Blue Heron, Trumpeter Swan, American Kestrel, River Cooter
I'm sure the swans wouldn't appreciate having a bird of prey in the exhibit with them, even they don't pose a threat to them. That and the herons might well bully the kestrels.
10. Coyote, American Badger
Ooh, interesting. A nice symbiotic relationship in the wild, but I wonder whether they would become hostile towards each other when the need to hunt is taken away? Who knows.
11. King Vulture, Crested Oropendola, Scarlet Ibis
While they are primarily scavengers, king vultures have been known to prey on lizards or injured animals, so I would probably steer away from this one.
13. South Polar Skua, Ivory Gull
Any young gulls or eggs would not last very long.
14. Atlantic Puffin, Pigeon Guillemot, Surf Scoter, Leopard Shark, California Sheepshead, Garibaldi
Very interesting one and great idea. Probably some kind of 3-level viewing. Very nice. Would be intersting to see how the public (and the birds) react to having sharks in their exhibits
15. Galapagos Dove, Marine Iguana, Sally Lightfoot Crab
Well of course all three of these species are essentially impossible to obtain but I'm pretty sure it would work if it happened.
17. Panamanian Golden Frog, Green Vine Snake
Almost certainly not a good idea. Vine snakes eat small lizards, rodents and amphibians. Also, even if it were a species that didn't potentially eat them, the golden frogs are best kept out of mixed exhibits due to their status in the wild

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18. Green Anaconda, Rainbow Whiptail
Whiptails would either be constantly stressed or eaten as a light snack.
19. Bongo, Yellow-Backed Duiker, Black-And-White Colobous, Congo Peafowl, African Gray Parrot, Great Blue Turaco, White-Necked Rockfowl
Nice one! Think it would work, unless I've missed something.
23. Reticulated Giraffe, Black-Backed Jackal
Don't think so. A male giraffe would chase a jackal around all the time, and likely kill it eventually. If a calf were to be born, the giraffes would kill the jackals as well. Probably best to keep the giraffes for a savanna mixed exhibit or just by themselves.
22. Aardwolf, Aardvark, Yellow Mongoose, Gray Crowed Crane
I genuinely think this might just work! I mean the Aardwolves and Aardvark are nocturnal and the others are diurnal, so that might be a bit of a nuisance when designing an exhibit, but maybe?