Canada, while a different country, follows domestic for most purposes. Service, CPU, ticketing rules/fees, etc.

For revenue tickets for sure, like domestic, a layover to Canada over 4 hours (unless that's when the next flight is) is considered a stopover. While I'm not 100% certain it's the same for awards, I can't imagine it would be different and that would be consistent with what you are finding.

The similarity to international flights for Canada is limited pretty much to lounge access for F or UA gold and above, as well as the fact you'll need to pass through immigration after landing.