The previous landlord took no deposits, and criminal activity was the "norm."

As you likely already know, it's pretty much impossible to find a DST that outperforms, if even matches, the returns of syndications (have done a lot of projections with those, too), and they are expensive, rarely offer value add opportunities, and have a long hold period.

I'd suggest you interview at least 2, then you can decide if you're both a good match.   

To especially confirm that, check if the unit inside is still there because it'll have to match.

If they never received a satisfaction of mortgage letter and the lender does not have the necessary documents, you can try to obtain a lien release from the Federal Deposit Insurance Corporation (FDIC).

You should be able to keep the deposit and send them to collections for the AC and any unpaid rent. 

I fear that since I want to have my first deal so bad, I will force my "promising" deals to match my financial objectives, what would you recommend to keep my head focused and not let my emotions rule the analysis of my deals?

Once you have a purchase agreement and earnest money deposit together, how much does it cost to have this accepted and recorded with the title agency for escrow?

We also accept deposits through these two platforms. 

I would recommend attending local meetups to meet investors who you have a personality match with, or to meet someone who is doing exactly what you want to do.