We took a nearly 10months old in march a couple of years ago. The weather was nice. Much cooler than Sydney.
We took an umbrella stroller and a hiking backpack for Darcy and she was fine. We flew though.
Up past Launceston I think it was was a cool Seahorse farm, a platypus place and a fariy penguin night walk which Darcy loved.
I don't think they do the Cadbury tours anymore? not sure, but the ladies loved her on that and she got twice the 'loot' of anyone else lol.