We then used that to buy a 4 plex and put all of the 'cash flow' towards paying that note off within the 5 years and now have both properties cash flowing nicely for no more input from our SOLO401Ks.Right now I am working with a seller that is looking to sell a portfolio of about 10 units with seller financing and he is open to doing it non recourse.

In that case, do I need to pay interest for the 3 days that I don’t have the money?

Jerell,Credit and rental history are probably your biggest worries - i.e. do they have the funds to pay and will they pay, and do they owe to their prior landlords. 

(And offered to pay to fix it)What concerns me is she did not reach out to the person below or contact anyone .

Ideally, I was hoping to pay off this mortgage in about 10 years.

It's much cheaper to pay a professional that keeps you out of trouble than it is to pay an attorney to fix the problem.

With interest rates so low we have refinanced into several 15 year mortgages with the goal of quickly paying down/off a few properties.

🌴PS - It might also be a tax write-off for you. 

The property comes with one unit occuped and they are paying below market rate.

I have been eyeing a property that is listed as a fairly new mobile home sitting on almost a full acre, checked out tax records etc and the land does belong to the seller.