It's difficult to forgo payment entirely, it's not like you can walk into a grocery store and ask for free milk and eggs because you lost your job.

I had a contractor walk the property and said material cost is about 10-15,000.

Come up with all the options - including walking away from the contract - and present them to seller.

Think of the big picture - do you want to walk away from a great deal due to a few grand?

Very similar to their Premier Agent system.Zillow's instant offer is verified by a real estate agent who meets the seller and walks the property to verify condition (Zillow also does inspections to drop their price further if Seller accepts it) but the agent's goal is to take a listing by showing the seller how much more money they'd net, NOT to talk them into taking Zillow's offer.

Realtor if they were acting only in buyer's interest might just tell the buyer to walk away.how much is the value of the transaction?

When I walk into a house, I can't tell if something needs replaced unless it is obviously damaged.

Do video tours or show up at the rental (assuming it is empty) and let them walk around themselves. 

Although it is possible that my appraisal reaches the LTV required for me to walk into a 75LTV Fannie R&T, I am trying to come up with strategies if it does not appraise.

Win-win for a motivated seller who wants to sell NOW.No kidding you simply put on your contract i am buying for PROFIT or LOSS  my attorney taught me that on in 1975 it works like a charm. if they dont want to take your price you simply list it and make money there.. not just walk away with yet another lead you spent money to get that turned into dust.