If for some reason the deals falls through, what is my (the assignor) responsibility to the seller should the buyer (assignee) backs out for whatever reason?

The major conflict is that I would need to spend nearly $13,000 instantly to resolve the roof leaking and falling chimney.

You never know, circumstances can change, the owner might meet some cowboy and they could fall in love and get married in two years and then they could pay for anything that might be required.

Is a sorry state of affairs when you start paying criminals for their wrong doings.Cash for keys started out with tenants who were victims of foreclosure, due to their landlord not being able to make their mortgage repayments.

Gurus love to teach BS, and everyone falls for it.Joe Gore

Then you let it fall into foreclosure.IIRC there is some exception, but I don't recall the details.  

This creates a slip and fall hazard.

With you doing renovations in the fall into winter months, you may experience some set backs.

Since you have had the house for 2 years you can probably still get the pmi to fall off without the refinancing. 

The pmi automatically falls off when the loan value reaches 78%.