I would prefer a loan with a lower interest rate, below 5 percent, but if you run into the perfect property with multiple offers, why not sweeten the deal with an all cash offer.

I submitted my bid, using a buddy’s proof of funds, waived my own commission to sweeten the pot, and got the house!

You can even sweeten the deal with "sign lease with new owner within x days and receive..."

Unless you already have that $25 monthly PMI verified with your lender.The cashflow seems to be cutting it close, maybe try to sweeten the deal for you by getting some better terms to increase the cash flow.

Would this small regional bank be willing to finance it to your son under favorable terms to sweeten the deal, especially if the alternative would be HML with 10%+ rate + 2% in points to originate?

The idea of sweetening the deal for the contractor is a great idea! 

If thye give you a hard time about it, tell them you will sweeten the pot by increasing their net proceeds.

If people need something to sweeten the deal, instead of just writing down "big screen TV", describe it, have them visualize it, even leave a picture of it for them to hold in their hand and think "wow, wouldn't it be nice if we had one of these?"

Look for ways to sweeten the deal so she will accept your financed offer.

You might consider submetering, which would have a nasty little one time cost, but could then you could chargeback their utility usage accurately.The cheapest, easiest solution in your case is probably to charge a higher rent then offer the "free utilities" as a sweetener.