I don't see how any Flanker from China could reach Australia, and Australia seems intent in being neutral with any China related conflict.
I do agree that the Su-35 still has something to offer to China. My personal belief is that extreme self reliance by itself could lead to stagnation. Having considerable foreign input is great for your creative and technological soul. These planes can serve as a standard for domestic manufacturers to match and it is a good way to keep them on their toes.
But my personal beliefs means zilch to the Chinese leadership. China isn't happy dealing with Sukhoi, and I am also left with the impression that neither does the many Russian subcontractors that supply Sukhoi. Salyut ijn my opinion, doesn't seem to be happy supplying engines to Sukhoi which in turns supply them to China. Sukhoi is acting like a middleman creaming on margins and I suspect that despite payments made by China to Sukhoi, Sukhoi isn't paying its suppliers in time. I believe Sukhoi is hard up in funds financing PAK-FA, and it already went into court battle with the KnAAPO factory over the MKK contract proceeds. The result leads to suppliers withholding their supplies to Sukhoi, and that holds up J-11 production and has effects on the spare parts pool supply on the operational J-11s.
The fact that China is going directly to the contractor making the OLS-31E tells me a lot. Used to be all these parts, components and avionics are packaged into kits, which is then supplied to China to make the J-11s. The fact that China is sourcing the parts directly tells you they just want to bypass the entire kit process, and the Russian contractors are more than happy to oblige. Similarly, China would probably source engines directly from Salyut or UFA. One of the reasons why Salyut appears to be happy with the AL-31FN purchases for the J-10 is because these engines are dealt directly to the end customer, not to a middle man layer.
Regardless of the present benefits of the Su-35 or even the Su-30MK3, it probably isn't going to overcome China's negative impression of Sukhoi as a reliable partner and supplier unless Sukhoi can reverse that image. Which makes a complete platform buy unlikely. Maybe China will continue to buy components to fill gaps in their own technologies, but they won't buy a complete aircraft from Sukhoi again, unless Sukhoi does something. Besides, if there is going to be a buy, I would think that the Su-33 and Su-34 would be higher in the list now than the Su-35.