The new NEC 2020 is out and it states (note that it is for "locations that are supplied by single-phase branch circuits rated 150 volts or less to ground are required to have GFCI protection for personnelYou have to check and see if your city/state require NEC 2017 or NEC 2020 or neither (like Phoenix AZ)  but it's good to follow the code anyway.2020 Edition: Section 210.8Dwelling Units 210.8(A)All 125- through 250-volt receptacles in the following locations that are supplied by single-phase branch circuits rated 150 volts or less to ground are required to have GFCI protection for personnel.Bathrooms210.8(A)(1)Garages and accessory buildings210.8(A)(2)Outdoors210.8(A)(3)Crawl Spaces210.8(A)(4)Basements (finished and unfinished)210.8(A)(5)Kitchens210.8(A)(6)Sinks210.8(A)(7)Boathouses210.8(A)(8)Bathtubs or shower stalls210.8(A)(9)Laundry Areas210.8(A)(10)Indoor damp and wet locations210.8(A)(11)Boat Hoist555.9Other Than Dwelling Units 210.8(B)All 125-volt through 250-volt receptacles supplied by single-phase branch circuits rated 150 volts or less to ground, 50 amperes or less, and all receptacles supplied by three-phase branch circuits rated 150 volts or less to ground, 100 amperes or less, installed in the following locations are required to have GFCI protection for personnel.Bathrooms210.8(B)(1)Kitchens or areas with sink and permanent provisions forfood preparation or cooking210.8(B)(2)Rooftops210.8(B)(3)Outdoors210.8(B)(4)Sinks210.8(B)(5)Indoor damp and wet locations210.8(B)(6)Locker rooms w/shower facilities210.8(B)(7)Garages and accessory buildings210.8(B)(8)Crawl spaces — at or below grade210.8(B)(9)Unfinished areas of basements210.8(B)(10)Laundry areas210.8(B)(11)Bathtubs and shower stalls210.8(B)(12)Both Dwelling and Other Than Dwelling UnitsCrawl Space Lighting Outlets210.8(C)Specific Appliances210.8(D)Equipment Requiring Servicing210.8(E) [210.63)Outdoor Outlets210.8(F)Sump Pumps422.5(A)(6)Dishwashers422.5(A)(7)Swimming Pools and Similar Inst.See Article 680* Other GFCI requirements scattered throughout the NEC.

It's considered an accessory use to your primary residence.

A property is still considered a SFR if it has an accessory dwelling unit (or you can use it to build an ADU) -- it just can't be a true multi-unit property.Cheers!

Then add back in a few vintage decorating accessories in the house.  

Detached garage with accessory unit on top. 

It probably doesn't matter...conventional guidelines won't lend on a MFR with accessory units.

I think the term you are looking for is accessory apartment.

Or, if it is a legal sfr with an accessory unit, it will be appraised as 1 property with an accessory unit.

The other option is a single family with an accessory dwelling unit.

(A) One ADU or JADU per lot with a proposed or existing single-family dwelling, if all of thefollowing apply:(i) The ADU or JADU is within the proposed space of a single-family dwelling orexisting space of a single-family dwelling or accessory structure and may includean expansion of not more than 150 square feet beyond the same physicaldimensions as the existing accessory structure.