1. It is very common in Canada for a person with wealth acquired outside the country to apply for a home loan. At the time I was approved as a guarantor for a home loan for over half a million CAD, I had only been in the country for 2 years, and had no credit history with any Canadian institution (out of laziness I just was added to my wife's accounts as a signer and cardholder when I moved). They accepted copies of my American credit history and bank statements, but had no real way to verify their truth. In the US, I don't think that (relatively) wealthy immigrants wanting a home loan are nearly as common. Richmond, BC is a great example of this: avg home price is 1.5mm and 60% of the residents are immigrants.

2. Canadian mortgages are refinanced every five years, traditionally (it is possible to get a longer term, but very uncommon). Combine this with the fact that Canadian real estate has ALWAYS gone up (until now), and financing a home really wasn't a risky thing. If a bank didn't like a customer, they could refuse to refinance after 5 years. If a bank foreclosed, they were basically guaranteed to be made whole.