I doubt Australia goes further away as they face Argentina tonight which I think will "massacre" Australia
Most likely you are right here. Australia had a big portion of luck to get there, a weak Denmark unable to score and a lucky goal for Australia itself. Possibly, the game wil be similar to what happened to them in group stage, when France beat them 4-1.
Poland has been very lucky to get there as well, when Poland was hoping in the 3rd round of group stage that Argentina only wins 2-0 and Mexico doesn't score one more goal. Huge luck for Poland and I expect a massacre against Poland from France as well.
I also wonder why Netherlands had an odd 1.96 against USA and this scared me so I only bet on them to qualify further at 1.45 which I think is like a sure bet.
Sure, odds have been strange for that game but since Netherlands have been playing very effective so far (not many attemps on target), maybe it's for a time when Netherlands are less lucky. But turned out to be a good bet, Netherlands won 3-1 against USA.
In addition, odds are looking interesting for Japan to qualify against Croatia, I don't know why bookmakers are favoring Croatia so much. Croatia vs. Belgium has been very lucky for Croatia...