I've just purchased my first Investment home with the intention to extend the parking space and convert the dwelling to a duplex where I'll live in one unit and rent out the second unit. 

Another great option in Tampa is to find a house with an ADU (Accessory Dwelling Unit) or MIL suite you can live in while renting out the main house to cover your mortgage.Feel free to reach out if you ever want to discuss options or just dialogue about strategy that fits your unique situation.- Alton

The City has fast-tracked ADUs (additional dwelling units)--seeking a multi-unit building with an existing vacant garage with the ability to build out one or more ADUs is an excellent strategy.

Vacant Dwelling with Renovation.

Check out United Dwelling as well.

Nationwide the ratio of dwellings is 2/3rds owner occupied and 1/3rd non-owner occupied. 

They (1) forbade any use deemed to be commercial in nature, including down to the level of "renting even one room", they then (2) forbade any residential use of any building other than the main dwelling unit, and so on.

In regards to financing, I’m just unsure if FHA has restrictions against Accessory Dwelling Units (ADU) attached to an FHA financed 4plex.

1117-19.1 Dwelling units: Every dwelling unit shall contain a minimum gross floor area of not less than 150 square feet for the first occupant, and 100 square feet for each additional occupant.

Depending on location but infill its normallyCondos, stack towns to rowtowns Suburbs are residential subdivisionsMostly end user dwelling in Toronto area..Where you at?