If they do intend to go the route of Pygmy Hippos here, I'd hope they plan to construct at least one indoor enclosure in the barn too (with viewing). The size of the elephant barn would easily allow this.
This would effectively also allow two sizeable enclosures to be built on the outside; with a third off display behind the barn.
Yes, that would not only be enriching for visitors but fulfil a practical purpose in allowing Taronga to retain offspring bred on site into adulthood.
By the time Taronga receive an Australian bred bull (assuming that’s the plan), who then matures to breeding age and produces young, the breeding pair at DDZ and possibly Melbourne would have well and truly established themselves as suppliers to other zoos within the region, who will have little incentive to import Taronga bred calves. Unless they can accomodate their own surplus, they may not otherwise get breeding recommendations.