I have a spreadsheet with a summary tab that clearly lays out my monthly/annual cash flows, portfolio loan balance, equity, etc. 

How high do you plan to let the HELOC balance get, do you have enough other cash to pay off the HELOC should the bank call in the outstanding HELOC balance in full?

Things like the rule of 78s causing them to pay towards unpaid interest before principle or balance is paid down.

If they see that there is a balance due, that's a red flag that a mechanic's lien may be filed, which creates potential for a title claim.   

He consolodated to one loan with balance of 100.   

I am trying to balance privacy and security in my 12 unit.

Buy the property subject to the note/mortgage they just got and have them carry back a 2nd mortgage for the balance owed.

It's a foreclosure and the listing price seems to be ~the remaining debt balance, but I imagine the bank would be willing to take less since it has been posted for so long.

Since answers will depend on investing strategy, let's just assume we're talking about single family houses (or even small multi) with a good balance of affordability, cash flow, and a reasonable chance for some appreciation over the mid to long term.

It provides a nice snapshot of the balance sheet.