Needless to say he has scared off all of the potential buyers for our home.

Especially as a buyer, where you don't have to pay the cost of the agent (the seller does).

Having said that, I have had many buyer clients that receive money from non-US persons for down payments, to show post close liquidity, or to pay all-cash for real estate.

Even with a transferable warranty it can scare aware home buyers if selling this down the line is an exit strategy. 

howdy. i had a 4/2 house in milwaukee for 9k in riverwest that i could not sell for 15k a few months ago. wow i couldn't believe it. i came on here and found like 5 buyers and 3 of them went to see the house and still didn't sell. so i gave up on milwaukee. my market in dallas is wayy better. i get houses 30k> and they dont last a day

The seller pays the realtor not the buyer

I don’t see why it would matter, but I don’t want to lose the deal over the buyer’s financing.

If you still don’t pay, the tax buyer will foreclose and own the property. 

That's exactly what I did when faced with this issue, meaning I had a buyer under contract before I actually closed on my purchase.

I'm going to be honest so I can paint the picture as to where I am as a new investor: I've marketed for buyers, practiced calculating ARV numbers so see how that works, and have searched for properties.