What things can potentially cause a deal to go from pending to canceled between executing the effective date of the contract and closing?

They can also execute a General POA to sign any document with their name.

The defect list could be 20 pages long with an asset like this and the tactic just takes this all off the table as any further negotiation once the contract is executed.

The key is to have it in writing and agreed to prior to execution of the lease and to have the "conditions" explicitly detailed in the amendment and recorder at the time of the showing.

Are you willing to front your borrower cash to purchase and execute the note and DOT after the purchase escrow?

SELLER'S UNLIMITED RIGHT TO CANCEL: At any time after the execution of this Agreement, the Seller shall have the unlimited right, at Seller's complete and sole discretion, to deem this Agreement null and void.

If you want the "other person" off, they must execute a quit claim deed as the grantor to you, you don't sign anything.Didn't follow the 1200 amount, but you need to make a deamnd to the older lender to provide a deed of release and they are waaay past due in doing so.

If you plan on executing the deed make sure the deeds are held by a neutral party/trustee.

What if they don't properly execute the investment plan?  

If it's worth $50k retail, list is for $57k for the additional risk and they don't have to pay for the house for 3 yrs so it will be worth a lot more than $50k when they actually convert to purchase (execute the option).