The Rocky Mountains area wasn't planned to be present at opening, but part of a proposed part 2 and 3 alongside a South American Pampas with Maned Wolves, and other things such as onsite accommodation. Presumably they were planning to expand more into the surrounding parkland.
On one of these original maps, bison were also planned to replace hippopotamus alongside capybara. Capybara do now of course inhabit part of the area that was originally planned for hippos, with the rest of the paddock housing dromedaries.
I remember seeing a plan that had both orangs and gorillas, as well as chimps.
Sri Lankan Leopard is another species that was in the original plans but was never acquired.
Also interesting to note is that the Australian section was originally planned to be more locally-focused. It was going to be called the "Cumberland Plains Bushwalk" and was planned to show species that would have inhabited the local area before European colonisation. Instead of Kangaroo Island and Red Kangaroos, and Yellow-footed Rock Wallabies, there would have been Eastern Grey Kangaroos and Brush-tailed Rock Wallabies. Not sure why these plans didn't come to fruition; perhaps KI Roos and YF Rock wallabies were just easier to acquire.
Yes, it was Sun Bear, planned to be housed in the site of the current red panda exhibits.
(Sorry, this is probably getting a bit off topic for this thread)