I've found something seriously interesting here - it's probably the best lead any of us on this thread have had!
The following link is to the website of Studio Hanson Roberts - an architectural firm that have designed a number of Zoos Victoria exhibits in the past. Scroll down to the 5th project on the page and you will see "Melbourne Zoo Masterplan" - it doesn't give any written info but it does show a map - which you can enlarge by clicking on it.
ON THE BOARDS — SH|R Studios (shrstudios.com)
I have no idea how flexible this plan is, but for those of us hoping for Indian Rhinos (as I am), then judging by this it's not looking likely...
That said, I'm really not sure how much to read into this - perhaps this is just a basic "first draft" designed by the architects so that they can put a picture to the project.
Keen to hear what others think - because this looks nothing like what we have all been talking about for the past 40 pages!
BTW, the website itself is great - it has a lot of projects they have done at a lot of zoos including Auckland and Werribee.