So what you really want is to communicate mutual benefits for each party.

Once that is done you can get a list of the parties that own those properties and send them a specific letter with offers and they will call you. 

But when you have to rely on a third party to do things correctly, don't hold your breath. 

I hope to live in the second while flipping the third.

Im pretty sure no individual party will be able to secure a loan of this size.

Get information for all parties concerned.

I want to rent it over and over to responsible parties who will pay more than they would if they didn't have a Right To Purchase.

Yes, because the top half of the bottom third is...Where starter homes are located...Where I used to buy as a newer investor and continue to buy as a seasoned rehabber...Are a bit older so they tend to have the "right things wrong" with them...Because there are more houses at this tier than at the top...

I didn't find any information from the IRS, but found articles from several 3rd parties (custodians) that said it should be allowed.

You could try and just use third party sites like Zillow or Redfin but their information isn't 100% accurate and/or timely.