They can provide you with a loan letter that states the average time to close a loan and the maximum amount that you are qualified for.Another item you should consider is your office location.  

I'd keep the holding fee send them notification that you received their letter asking to be cancelled / released from the lease application and have re advertised the property, with the terms clearly circled on a copy of that holding deposit agreement form.This is common practice, if someone signs a holding deposit agreement and cancels in writing that they no longer want the apartment before the lease is signed then the property manager has the right to retain the holding deposit fee if it is clearly written in the holding deposit agreement form.You basically have taken the unit off the market for other interested parties, and have lost the opportunity to get another tenant to rent during the time the application was being processed, you the property owner did not cancel.. they did... if you the property owner had cancelled you would be required to refund the holding deposit. 

He says the same owners Will owner finance the 5th property to me for 180,000$ which is the price they agreed on from 200,000$ @ 10% down @ 5% interest 30 year Loan with a 10 year balloon.

They can get a loan letter to you that states the average loan closing time and the maximum amount that you qualified for.Another thing you might do is to find your office location that is convenient and has a minimal of distractions.  

Essentially, if you finance 3 or fewer properties in a 12-month period you will be exempt from these rules WITH THE EXCEPTION OF...balloon payments.

@Anthony Johnson It is imperative that you get copies of leases and estoppel letters from each tenant confirming their lease amount and security deposits.Regarding the "disgusting' unit, you can give them a 7 day notice of non compliance with the opportunity to cure (cleanup) within the week.

The (non)lender refused to complete and send a payoff letter, or acknowledge any loan amount or interest rate, when the 'borrower' went to 're'finance.

I'm starting to think about sending out yellow letters again, but I very definitely am looking for a different market to farm.

If you aren't local send letters and make phone calls to the owners. 

Try using letters of intent to seek out seller interest which can then be followed by a real Offer to Purchase contract.Farm with letters but get serious with offers.