They handle non-emergencies (noise disputes, safe passage into a home to remove items, etc).

What is the best way to put aside this money safely and in an organized fashion.

That’s the best bet.

It is a very safe, liquid, tax free, asset protected and with a moderate growth.

If you hop on AirBNB and there are lots of places to rent way out in the future but few now (assuming there isn't a "busy season"), that could be a positive sign.18 acres isn't enough space to hunt on safely or ethically except maybe wingshooting or bow deer depending on location, so that's probably out...

The seller wants a larger EM, and I’ll bet it will non refundable, because you’ve had multiple extensions and the seller is tired of dealing with it...if I were their agent I would ask for the same thing, or simply put the property back on the market.

What’s the worst thing that can happen, what’s the likelihood of that, and what’s can I do to safely reduce that risk.

The notice of default and notice of what is to come, may straighten this guy out a bit or it could send him looking for another place.If he intends to bolt, I bet he stops all payments.

One very safe way to do this is with a private mortgage note. 

Also invest in the best security systems you can get and do everything else you need to be safe.