How long it will take depends on what country will process her application. As far as the timelines of the European offices go, most averages are under 12 months.
If they are not ready to proceed, they can wait until closer to the time when they are willing to re-settle. While she can land in Canada and then return to Europe, she needs to accumulate 730 days residence out of every 5 years in order to keep PR status. They will waive the requirement so long as she is residing with her spouse, but there is hardly any point to them taking on the expense of the process if they are not ready to re-settle, especially as they will not be faced with a lengthy processing time.