"Agreement Subject to Partners Approval" (my favorite)"Agreement Subject to an Acceptable Appraisal By Buyer""In the Event of Buyers Default the Deposit Shall be the Sole Remedy"

Once the redemption period has passed, that lien holder's interest in the real property is extinguished by the completion of the Sale unless they choose to redeem.A junior lien holder with the power to foreclose can foreclose for the amounts due upon default or breach of contract, etc.

How much is the defaulting lien in arrears?

The defaulting home owners stop paying their mortgage for months, sometimes years. 

Ive got 4 units in long term default that we are going to have to clean out. 

For instance, even if you structure through an LLC for instance, you're still going to be personally responsible for the loans and possible default, so there's a good chance that they'll likely want to see both good credit history and sufficient income to cover the loan.  

@Steven Rogers @Douglas Dowell These days lenders will look at the property first to see if it is a good investment vehicle. they will now look into you to see if you will guarantee the loan personally in case of default Commercial pre-approval is non-existent as it has no bearing on the investment situation.

If the bail out and cause damage, use it, if they buy, return it to clear up your books and they can then apply it at settlement.You can, since you're in a hurry, use a standard purchase contract, use a standard addendum and the delete or amend all contract provisions for default of buyer for failing to purchase and add that the sale is at the option of the buyer.

Lot's of stuff put in leases isn't legal or enforceable.Go read your contract ( lease agreement ) for default provisions.No legal advice.    

If your rent covers your expenses, it doesn't matter what the market value of the property is.If your rent covers your expenses AND cost of leverage, it doesn't matter what the market value of the property is.This is true for leverage UNLESS your loan terms comes to an end, and you are underwater, then you face default since a neither a refi nor sales may pay off your balance.You can mitigate the risks of going under water by not over leveraging.