In addition, due to them being eligible for conventional non-commercial financing they typically have lower cap rate than 5 units and more.  

I am using a conventional FHA loan to acquire the property.

Get a conventional mortgage.

I have learned once again, No one cares about your properties like you do.

The code being cited by the inspector is below if you care to bother.Thank you.https://codes.iccsafe.org/content/IPC2021P3/chapter-7-sanitary-drainage#IPC2021P3_Ch07_Sec708 Could you put cleanouts within the interior (is there a basement?)

They may need to be careful on this one as that may impact his DTI ratio. 

If you just want to build your cash reserves then flipping is the way but just be careful - that too takes a lot of work and research to make sure you don’t lose money.  

These modifications are carefully crafted to incorporate ADUs seamlessly, aiming for a delicate balance between increased urban density and sustained neighborhood character.

The big thing is always focus on protecting the public, disclose, and take care of people.

9) adding multiple ADUs or adding an ADU to a quad looses F/F conventional financing.