I have two ideas that I personally think are really cool. The first is an exhibit called Living Fossils. It would feature, as the name suggests, animals considered to living fossils. I'd like the headlining species to be a crocodilian. I think it would be really cool to have a state of the art exhibit for them so you can see them at different angles. I think the best species to represent them would be the Cuban crocodile, because they are the best runners of the extant crocodilians, and some prehistoric crocodilians were more ground-based and had impressive running abilities. I think it could be complimented by using living fossil plants in the landscaping as well. As for the theming, I think it would be cool to have it look like an archeological site with mock fossils of recognizable extinct species on the ground or on rock walls.
My other idea doesn't really have an exhibit name yet but its based on animals once thought to be cryptids, mythical, or hoaxes. Platypuses are kind of the poster child for this, so it would be cool for them to be the headliner. I understand that they are a very difficult species in captivity though. I think okapis could also make a great headliner if that didn't work out. As for the theming, I'm not quite sure the direction I want to go in overall. Some things I definitely think would be cool is signage about each animal's history of discovery and why they were thought not to be real (along with the normal stuff zoos would put on their signage). I really like doing the signage in the style of a bestiary. It would also be cool to have statues of well known mythical creatures, like dragons, unicorns, griffins, etc, Elephant Odyssey style.