FHA does not allow an accessory unit unless the primary is a single family, so even if both buildings were on one piece of land and deeded together, it would be ineligible for FHA financing.

We live on 3 acres in "wine and peach country", so we came up with the idea of building an accessory dwelling unit (ADU) on the property to use as an AirBNB. 

Just recently, the city is now permitting Detached Accessory Dwelling Units in R2 (Single Family) zones. 

The "Workshop" was converted into a permitted 2bed/1bath "ADU" (Accessory Dwelling Unit) which is rented long term but I plan to also rent on Airbnb once my tenant's lease is up.

Hi All,I see a lot of homes in my area that have detached garages that would make perfect ADUs. With the relatively recent changes to the ADU policies, I would love to find a way to invest in them. Is it possible to b...

However, Fannie Mae does allow certain exceptions to this policy for boarder income and properties with accessory units.

Hi Stephanie,If you want gas, I have only four words for you.Propane and Propane Accessories!

Another item of note: Increases the maximum household size permitted on a single-family lot from 8 to 12 unrelated people only if the lot includes two ADUsI own a duplex near the University of Washington that I could add a DADU (detached accessory dwelling unit).

Definitely thinking Single family with an accessory dwelling unit may be an option though 

@Jason MeadowsThey’re legally called ADU Accessory Dwelling Units, and while it seems easy you can buy or build a tiny house and drop it there and rent it, you’ll need to go through the ADU permitting process (setbacks will be the issue), and the biggest expense of construction is getting water, sewer and power out to it.