Hey, out here in the west end, Sauga a few years ago they got their heads out of their asses and allowed second units in single family dwelling.
Annual fire department inspection fee to be sure all exits remain viable etc are higher if the owner does not live in the house.
A place 4 doors down from me was one of the first to convert. They extended the back of the house to enlarge it. Widened it a bit too to allow separate entrance to side of the two car garage and an added staircase to the basement and the second floor.
So the place now has main floor split in half with two kitchens and dining and a shared laundry. Extension on back gives two living rooms, and basement bathroom and second floor bathroom. One units bedrooms in basement, other bedroom's on second floor.
It really is a nice conversion. Yes about 8 months of disruption. But that is to be expected.
I surmise it is a harbinger of thing s to come around where I live.