It was stage 2 of the carnivores which was following the opening of stage 1 (Lion Gorge) in 2014.
Lion Gorge opened with Lions, African Wild Dogs and Philippine Crocodiles but there were plans for both Giant Anteaters and Aardvarks as well, but unfortunately an IRA could not be completed in time for either. There was a point where Melbourne actually had a male that they were going to import, they just needed the IRA.
Stage 2 was to follow and open in 2017. It initially was going to have Snow Leopards, Sun Bears and Komodo Dragons (this was prior to the opening of stage 1), and then was later advertised to have Snow Leopards, Spotted Hyenas, Tasmanian Devils and Coatis. Sometime in 2015/2016 Spotted Hyena were then removed from the plans and replaced with Sumatran Tiger. Not sure exactly why, but maybe they just simply decided to hold them at Werribee instead (as is the plan now).
In 2017, stage 2 opened as it currently is with the Snow Leopards, Sumatran Tigers, Coatis and Tasmanian Devils. A fraction of what it was meant to be imo.

Not the first time Zoos Vic have done this - *cough* growing wild *cough*