Regardless, the lady who has possession now is not going to turn over the property without kicking and screaming and probably a court battle...if it went that route

Use the enemy method and the search function in local Facebook groups.

The last time the house was at auction it sold for $398K (owner filed bankruptcy and negated the sale, then ignored the court until they dismissed his case).

Easiest in court to prove, and to defend if you have to.

There is some room for further negotiations, but now you have placed an anchor price and showed the criteria you need to get the deal done, so the ball is in the seller's court now. 

And if there is a conflict the court system will bend over backwards for a dead beat tenant or squatter and hold landlords to a entirely different standard. 

Honestly, we should have been easy clients - we came to him with a plan in place wanting his help on claiming REP status, setting up a cost segregation for a rental property bought and functioning in 2022, so that we could file for 100% bonus depreciation for that tax year.

If you don't hear back in a timely manner (like in two weeks), write another letter and say that you are going to be taking it to small claims court but you are willing to settle for "x" amount out of court. 

I signed up for Deal Machine but it looks like they already removed the texting feature but I do like the driving for dollars function.

Once you have a shortlist, sign up for an account with each one and test them extensively to see how they function.