Mordeth, there’s one more thing you need to know. It’s not important for married persons applying for an APRC but for independent applicants you might still need your Income Tax Statements from the tax office. If you’ve been jointly filing taxes since marriage and your wife has been listed as the primary taxpayer (if you’ve been filing online this will undoubtedly be the case since ARC numbers aren’t processed by their online filing software) then congratulations! You have ceded a perpetual Power of Attorney over access to these documents of the relevant years to your wife.
I wrote about it here: A warning for foreigners filing joint taxes