It is amazing how many times I have seen the cash flow represented as rent - PITI and to compound the issue they did not realize the ADU would increase their property tax.   

Appraisals are always an issue due to a lack of comps.

There would potentially be some weight issues with the 2nd+ floors of some shopping malls, depending on what the potential tenant wants to store in the upstairs unit. 

I see some larger single family homes in areas that appear to be zoned R2 that, at least from a physical perspective, seem like they could work for this.

Feel free to inquire about their staff qualifications if it's a larger organization.2.

I've had them long enough to keep pushing up rents so that I am at the top of my niche, but know not to exceed it because I'm just about at the point where if I raised rents another $50-$100 I'd be crossing over into the lower end for larger units.

Maybe just try finding the deal and sending it over to a larger wholesaler for a JV fee?

Also make sure to build on a property located in a desirable location with larger pop density and if holding for rentals, charge median rent for that market as lenders want to see a bigger pool of buyers/renters available to occupy/sell. 

I have found it is beneficial to rent your smaller homes with the program and your larger homes (same number of bedrooms) in the private market.

Larger brokerages sometimes are in need of administrative work, which could earn you a steady income while also getting exposure to the field.