I have the information I need to send letters to the owners of said lots. 

My idea to buy a home is to get an 80% LTV 1st mortgage from a bank, take over that mortgage and give the seller a second mortgage for 50% of the 1st mortgage balance because I need some cash to cover the payments, which the amount of cash would be more than the remaining equity in the home.

Also, you are not buying at a premium and can allow the property to appreciate if that said area is historically improving. 

do you know how you will fund the acquisition? 

In 8+ years the answer to us has always been No.

Its the tug and pull of not enough inventory then everyone jumps in and floods the market. 

I just gave it a try with a random property I found for sale on Redfin and once the map updated and I clicked on the parcel it brought up a little context window that provided the mailing address (as well as other info).

Once you read the explanation below, you will understand how REALLY bad things can be if you don't get the letters but go through with the purchase.First, the owner/seller should have a clause in the lease requiring tenants to sign (or object to in writing) tenant estoppel letters if presented to them.

First there is no reason to buy a Townhouse "all cash" instead put 40% down and reap the benefits of an extrenly low rate, No PMI and the option to escrow.

Anywhere in the world.