A question to our hoofstock experts: what would be the ideal mixed-species enclosure for African antelope/gazelles in a traditional zoo setting? I understand few mixes are ever perfect, but I'm curious what would work the best in an enclosure that's about 1.5-2 acres and features at least 2-3 species.
I have been meaning to reply to this for a long time but keep not having the time. I can give you multiple options for different size classes of antelope that are fairly common in North America, and then you can decide whether or not you want only traditional savanna/bush veldt species or just a general mix.
For your large antelope, common eland, eastern bongo, and greater kudu are your safest options. All three species are generally on the calmer and more tractable side and are less prone to inter and intra-specific aggression. Bongo do tend to be on the shier side and are more nocturnal than the other two species, so they do not always show as well in larger exhibits.
For your next step down in size, eastern white-bearded wildebeest, scimitar-horned oryx, and lesser kudu are probably your best bets. All three of these species are a greater risk for inter and intra-specific aggression than any of the large antelope (specifically the wildebeest and especially in a mixed-sex herd), but they are generally calmer and easier to manage than their counter parts (sable, gemsbok, lowland nyala, etc.). Obviously, none of the
Tragelaphus species could be mixed together. Female waterbuck generally do quite well, but males are known to be aggressive towards other species, so they tend to not do well in mixed exhibits in more traditional zoo settings.
Finally, for you smaller antelope, impala and addra and Thomson's gazelles are the most feasible for mixed-species scenarios. All of these species are flighty, but they are generally the least flighty of their kind

Addra are probably the calmest and most tractable of this group, but the others can do well too if properly desensitized. The male gazelles would likely have to be kept separate, as they are quite infamous for trying to fight above their weight class.
For a smaller mixed-species exhibit with a bit more flare, lesser kudu, gerenuk, and Speke's or Soemmerring's gazelles is a mix that is doable, although the males would potentially need to be managed separately (specifically the gazelles again).