Another option would be to tell these guys you expect them to remove their machines and/or reimburse you whatever you might be out of pocket, and you expect them to agree to terminating the contract - or - you intend to begin interviewing class action lawyers.It's not blackmail - it's perfectly legal to "settle" using the leverage of agreeing not to sue in exchange for something.

If you do not do so, I intend to sue you in small claims court, and I will ask the judge to require you to reimburse me for all rent I have paid that was unnecessary due to your lack of attempting to re-rent the unit, plus any punitive damages allowed and my court costs.Sincerely,Your SisterI bet he knocks it off.  

If existing tenant wants to stay, they are to settle the debt they have between each other. they need to reimburse the other party for their portion of the deposit.

Would I be entitled to a reimbursement from the seller if I walked away?

They can file a claim with their insurer to be reimbursed.  

Rehab money is paid by the investor and then reimbursed in draws once the work is completed.

If they did not pay rent bring that to the attention of your lawyer, it could matter in whether you can get them out.Stop paying for any expenses for them immediately (you can always reimburse anything you want to or are found to be responsible for later).

Or possibly reimburse them for materials to take care of it.

A local agency may charge a fee to reimburse the local agency for costs incurred in connection with the issuance of a permit pursuant to this section.

You don't have to reimburse him any rent, but just take any rent owed out of the security deposit.I just get the impression that you're looking for a fight.