Legal status still decides whether the income can be underwritten. The City of Saskatoon requires a building permit covering egress, ceiling height and fire separation before a suite counts as legal income space, and a lender will not credit rent from a suite that cannot show that paperwork.
Expenses reduce the number that reaches an owner's pocket. Utilities, insurance, maintenance and vacancy between tenants all come off gross rent, and a home inspection, typically $400 to $600, is the way to price deferred maintenance before it becomes a post-purchase surprise.
A real number for a real address needs the suite's permit file and current comparable rents, not a general estimate. Get your hand-reviewed valuation from Joel Dyck.