So ADU rules can change depending on where you are in the county and city, and can be a moving target because rules change.  

I am targeting a minimum 7% cash yield for new acquisitions and I sensitize all underwriting assuming a larger op-ex ratio and a larger vacancy factor. 

How can a list that targets people that never even asked to sell their house urgently possibly be the best way to do it?

No I do not do ads, I do not do re-targeting, I do not pay a friggin cent on marketing or leads.Paying a fortune for lists, and then pay an other fortune to send mailers out to that list?

So you should trim the target purchase price to a deal size that allows you to have somewhere in excess of 20% down. 

Cynthia- I definitely agree with what the other posters have said, Facebook can work great as part of a targeted strategy if you know what you are doing (using Business manager, strong calls to action, systems/funnels, etc). 

I sent postcards back in the fall to a targeted group of landlords (about 500) and recently sent about 2000 post cards to a targeted group of small commercial property owners (12 towns) and the response rate for both was less than 1%.

Trying to see what types of return you have been targeting and seeing.

With regard to why you're not getting any responses from sellers, I think you have to look back an evaluate the type of properties that you have targeted. 

I would start by looking for a quality property in your target market that hopefully has a motivated seller.