My advice, if you want a Ford, only look at vehicles for sale by Ford dealers. That generally means they come in on trade, and any vehicle that is not clean enough, too many miles, etc., is sent to auction.
4 owners is not a problem per se as long as maintenance was done. I would be concerned about salt/rust coming from Canada, in a perfect world we would only buy used cars from Arizona...
My other question is about Canadian titles. I know there are states in the US that don't have a salvage designation (leading to
"title washing"), and if CarFax has as much info in CVanada as it does in the US it shouldn't be an issue.