Interesting, I wouldn't have thought that cold tolerance was a trait Australian need for figs. What sort of equivalent to the USDA Growth Zone are you in?
If it gets cold enough, I think the RdB brebas freeze a little more easily. Outside of that, I don't know why some of us with potted figs which are protected during the winter get brebas while others don't. RdB is also great because since it ripens so quickly, if you have a longer season you might be able to ripen 2 main crops. I go for the brebas and one main crop with plenty of time to spare after the main crop has ripened in my zone 5b. The brebas if you get them are a nice treat, even if their not as good as the main crop they are still better than anything in the store that time of year.
I'm not sure if you can get Petit Negra there or not, but for me it is different enough in taste from RdB and so far for me anyhow produces the best brebas of any 2 crop figs I have. Petit Negra is also a close relative of VdB/Negrone.