No if potential buyer have given you emd than you are under the assumption this is a serious buyer and will close on the deal but he has only a certain amount of time with his inspection period so if he backs out you still have time to fund another buyer. 

Optimize now to fill the vacancy quickly.

They’re quick n easy.

The only issue I've had is a small period where the laundry pods would always be empty at turnover. 

Also, I believe I saw somewhere that the mortgage won't count against the original owners DTI after a period of time if they show someone else is paying the mortgage.

I am wondering if transferring the cash periodically to a standard brokerage IRA account may be my best option.

I've been a solo broker for well over 20 years and can spot a serious buyer/seller very quickly. 

I am currently under contract for a property, and my inspection period has just expired.

I have clients doing 1 a quarter thats about the slowest to others that will go on a mini tear and I will help them buy 5 or 6 over a 45 day period then they go to work.But generally my busy folks will do 15 to 30 plus a year..

It is still a seller's market in many geographic locations, so you can ask potential buyers for an extended closing period and/or with options to extend the closing period.