@profiler already answered to your post, but wouldn't be possible to change your application with your wife as accompanying? That would be so much less troubles and also you would save a lot of money.
Regarding your point #3, does any of you or your wife have any family in Canada? If yes, have them write an invitation letter for your wife. If she is currently working, that's also a plus and I would suggest to apply soon for a visitor visa. Having a job, having a lease, whether in Australia or in her home country, are good to show ties abroad. The fact that she travelled is a plus also. Actually, you being yet abroad might be a plus as well. I would suggest that she tries to apply for a visa before you actually come to Canada.