We have not tried it yet. But, we sent our inquiry and got response clearly state that my wife (non-primary applicant) can enter into the country ahead of me.
Thus, there would be no concern, my wife would simply take the printout of answer from CO with her and show immigration officer if she is stopped.
Good news. My wife just landed in Australia one month ahead of me without any issue. No quesions being asked at airport.
Basically, anything possible as long as you try.