Since you won't be able to recognize it as a valid rental if you're charging under market rent and you also expect to be covering any house expenses that are outside of her budget, this seems the best choice. 

I am considering getting into this space (looking at some courses), but worried that its too late, and that deep local market knowledge/understanding of buyers/connection with developers etc is required to make this work, which only incumbent/long term investors will have and would be hard for a new entrant starting from scratch to catch-up...is my hypothesis valid in your opinion ?

.: I have similar result, only like 30 - 40% of data yield valid phone numbers.

Seller has 100% responsibility for revenue production, buyer has no controls of revenue production, it impedes the operations, etc etc.. 

And there is a lot of superior options out there in both product and methodology. 

Have you validated the information it spits out?

Reduce the federal budget deficit to 3% of GDP, achieve real GDP growth of 3%, and increase U.S. oil production by 3 million barrels a day by 2028.For real estate investors, these plans could mean major changes—and opportunities.

Unless something has changed but I hope they can speed up the production of them.

And, yes, there are years of data points to validate that just within my office, tens of thousands of dollars of wasted appraisal and inspection fees for deals (mostly not mine, thankfully) that had 0.00% of going anywhere but the "Loan Application Declined" bin. 

Using an insurance and bank loan product, putting $500,000 each year for 10 years so your family gets $2mm tax free each year forever.