Could Australia have salvaged SMS Emden?

Could SMS Emden have been refloated if wave damage after the Cocos action had been less severe?

Yes, probably, and Australia would likely have taken the recovered cruiser as a war prize.

Wave damage after the Cocos action governs the counterfactual. SMS Emden probably could have been refloated if that damage had been less severe. Australia would then most likely have taken the cruiser as a war prize. The condition of the grounded hull determined whether salvage remained practical.