I do see what you are saying.
There are good correlation calculators, which are pretty accurate that will give more precise data than what you get from just looking at the charts [see below]
Forex Correlation Calculator | Forex Correlation | Correlation Calculator
They are just 2 examples, there are lots of others, im not affiliated in anyway to either.
With regards to the AUD/CAD resistance, I see why you say that and im not saying your wrong, but bare in mind which levels are most important and carry most weight/momentum. The AUD has been going up against the CAD pretty steadily since the crash, a trend like this isn’t easily stopped.
Again, however, im not saying your incorrect, rather that if a level as low as that is strongly respected price does fall, then I would expect it to pass the last significant low, ie I would only expect a large sideways range, not a longterm down trend. This is where correlation comes in, what do other correlated pairs suggest etc.
Certainly not back to the drawing board for you, your heading in the right direction for sure.