Rest assured that what you are contemplating is unethical at best, and illegal and possibly could result in jail time at worst.

He assures me I'm totally covered with all the contingencies I require.

I had not decided if I would actually move at the time the relocation thing came about, so when I inquired about my options, my mortgage broker assured me that all that mattered is that the place is currently my primary residence and that there would be no issues with keeping it and renting it out, even soon after the refi.Well as the refi is proceeding, I decide to go along with the job relocation.

A small job like that, most "reputable" contractor could carry the cost and bill you once until the end, but what assures the contractor from not being paid by a client?

I like to fix things so I am assure that fixing wont be an issue for me.

Hiring PI's can get costly and averages about $1,000 per prooerty with no assurance that the target principal will sign up with your proposal. 

It is a pain in the butt the first time, I assure you :)

As a recent graduate, I can assure you that college students will pay for year-long leases regardless of the school session.

As a Broker/Investor, I can assure you, the "Hands down" greatest thing you can do to establish a relationship with a Realtor® is to offer them the leads you do not have any need for.  

I would explain the terms of the sale to the bank and assure them that you are going to make monthly payments during the time you are waiting for your buyers to qualify for a new loan I would then owner finance the purchase of the property under a land contract (owner financing) with sellers promissory note ( this would allow you to keep the 20k and it would be non refundable.