Now they want to be reimbursed because they repaired a property that someone else owns.Being the buyer I recommend not doing anything that is costing you money or time that you are not prepared to donate to the current owner.

Even if you set an amount for a deposit you don't get to hold the deposit anymore and have to file a claim to get any reimbursement for damages.Inset the damage deposit high since the guests doesn't actually have to pay it unless there are actual damages proven.If your one of the unfortunate ones that get most of their bookings from Airbnb dont count on them to take your side over the guest. 

It becomes problematic if you receive a check for reimbursement because the IRS will want to argue with you and assess tax on that amount.2.

They would not reimburse my money stating I was offered a loan.

Buying the mortgage (debt) is pretty unlikely play.Acquiring the equity of the heirs may be available however I would not go that myself because odds are high their equity will be reduced or eliminated by offsets due to medical card provider's claims for reimbursement. 

They didn't, so your agent should be fired or help reimburse you for that loss.

You can also set up medical reimbursement plans and pay for medical insurance that way, thus transforming personal expenses into business expenses.

If the borrower receives expense reimbursement, how will those be treated.

If the water/sewer was in my name, and my tenants reimbursed me every month (which I don't allow, the bill has to be in their name), I could never have the utilities turned off.

Our builder fee plus some overhead reimbursement is about 16 -18% depending on the job.