In my Junior year at Eastern University I met an entrepreneur name Joe, a guest speaker in a business course.

Once I have that, lenders will communicate the loan balance info and even negotiate the loan balance.Becoming a successor in interest via foreclosure auction on a junior lien is way more problematic than it should be, but that's my experience.

The old owners have an American Express judgement and it is now a junior lien on this house. 

It is not unlike a junior mortgage in that regard.  

In another thread I saw the following written: Generally, if you buy a junior lien, you want to make sure there is enough equity in the property to cover the 1st lienholder, that way, if the property sells, it now has a better chance to cover 1st & 2nd lien.Is he talking about the original owner's equity?  

Hello BP Nation:On MF transactions, Sellers often will carryback a subordinated note (junior to the bank note) in order to lessen the upfront capital requirements of the Buyer. 

On a short sale the seller can list for whatever they want but it's the lender on the senior loan and any juniors that must agree to that price.

From what I was told you want to track the senior mortgage and be sure you are not paying a junior lien.  

I don't think it makes a difference if it's a senior or junior lien, but if it does, please clarify.

Foreclosure wipes out liens which are junior to the foreclosing lien.