Either sit him down and see EXACTLY what the problem is and what it will take to finish up his portion....write it up and sign off on it.  

Good morning everyone,I'm writing from snowed-in Philadelphia.

Make sure the lender understands that this is a purchase and fast resale and try to get a response in writing from them because many underwriters will not know the specific requirements or that they can waive the requirement with a 20% down payment (they do not deal with flips frequently).   

When I write it down like this it almost seems like a no brainer but I am looking for some advice from those with experience.

That "short" amount is referred to as the deficiency.There are two ways to deal with it.1) As part of the short deal with the bank, get it in writing that they won't issue a deficiency. 2) Make sure that the tax deal is still in place so that the seller is not responsible for taxes on any deficiency that the bank issues.

If you were planning on partnership within a LLC, I would first write out LETTER OF INTENT where you both spell out what you want to accomplish and how- detail where the funds are coming from, who is doing what as well as what the percentages are loss or gain. 

Are closing costs considered write off's when the funds are intended to be reinvested in ones LLC or S Corp??

The owner is also open to taking a 20% second mortgage back.I told her I plan to write two offers, one for all cash and one with a 20% second mortgage.My question is what do you suggest I offer for each? 

My questions are:Can I write off the $20,200 i spent purchasing the land on this years taxes? 

As a professional organization, if he's a member, they can help hold him accountable by putting peer pressure on him.Don't stop pushing and make sure you keep everything in writing.