If you can dig up the refi closing statement or all the cancelled checks the title company might remove the lien.

Wall to wall carpet needs to be pulled but there is hardwood under some or all of it that could be refinished.

How long will their capital be tied up, when will they get some or all of the return?

What are the things that you once had to do all the hard work or all the hassle that technology has now helped you solve or manage?

OR... all of the above?.....

To get the buyer back, consider offering to pay for some or all of the buyer's non-recurring closing costs. 

They aren't entitled to that ARV, the claim to the original 100K or all of the 40K as if they are responsible for the added value by themselves, consider ownership risks, financial risks, market risks, making the deal happen, etc.

You have 45 calendar days from the close of the relinquished property transaction to identify potential like-kind replacement properties being considered for purchase and an additional 135 calendar days — for a total of 180 calendar days — to complete the 1031 Exchange by acquiring some or all of the identified like-kind replacement properties.1031 Exchange Identification RequirementsYou must  identify your potential like-kind replacement properties to your Qualified Intermediary within the 1031 Exchange time limits discussed above. 

In other words, by not allowing a credit of the option price paid and increasing the purchase price you make it more difficult for a tenant-buyer to purchase, making it more difficult is predatory dealing.On the other transaction mentioned prior to this post, fractional interest, congrats, but had your attorney been more up on tenants in common with a TIC Agreement that is not made of public record, you could have taken 49% and still taken the cash flow or all net revenue, just simpler without involving the lender.

Likely she will just collect unemployment and enjoy the holidays.The fact that you both signed the mutual termination can make it a law full enforceable agreement as long as some or all parts of the contract are legal.