Atwater Village "2 on lot" zoned R1. Can we convert garage 2 ADU?

[Dan A.]

We own a property with two detached units in Atwater Village on a ~6k sq ft lot that is zoned R1. The property also has a detached garage. Can we convert that garage into an ADU? The reason I'm unclear is because the property already has two units, it's not a SFR.

This looks like the key update in the 2020 change to the ADU law that makes this doable:

65852.2.

(D)(ii) The lot is zoned to allow single-family or multifamily dwelling residential use and includes a proposed or existing single-family dwelling.

Has anyone actually gone through the process of getting an ADU approved w/ a similar setup? I have a call into the city and waiting for a call back.

[Rick Albert]

The problem with the lot split through SB9 is the setback requirements.  @Will Barnard is correct.  However I  have seen at least one legal duplex on a R1 lot but it might have been a zoning change decades ago.  

Also consider on a practical basis does adding a 3rd unit make sense?  Where is the outdoor space for tenants?  Where is parking?  There is a lot more to consider.