If they are guarenteed, are the tenants collectible should they default?

Until you have a answers....I would keep paying them off as a default option just because it benefits you many ways....outside of tax.

Sellers who are going to hold paper need some type of reassurance that the buyer will not default on the debt.  

You have to be able to be able to stand out from the moment they get YOUR envelope.And in some cases, like defaults, you may have to leave a yellow post-it note on their door to get their attention.

I had a deal that I took 10 properties as cross-collateral and found out later that ALL of the properties had major issues and I couldn't collect on any of them after the borrower defaulted.  

Also lists possible foreclosures, looks to be ones that were served default notices.

If the borrower can not pay off the loan within the prescribed number of days, the lender can foreclose.Back in the good old days, when mortgages where assumable, they also did not prohibit junior liensFew lenders want to be in the position of holding a second when the borrower is in default of the terms of the first.  

They both became landlords by default and I took the opportunity to help them and get my feet wet with dealing with tenants.

We also can't read your contract, and if it specifies remedies for defaults, etc.  

By default all contracts are assignable. its only if they specify against it that its a problem.Lets get in touch i'd like to see if I can help you out with that