The income side is real but not automatic. A legal secondary suite needs permitted egress windows, proper fire separation and its own utility metering in many cases, and a lender will only count rental income toward your mortgage qualification once that legality is documented.
There is a lifestyle tradeoff too. Sharing a lot with a tenant means dealing with maintenance requests and turnover, and a $400 to $600 home inspection on both units is worth every dollar before you commit, even when the rental numbers pencil out well.
Joel Dyck can point you to Saskatoon streets where legal two-family homes are common and correctly documented. Get your hand-reviewed valuation from Joel Dyck.