If it's a 10 year old floor subtract the deprciation from the replacement cost and that's what she owes.Curious though if this is travertine tile, what 'pattern' is so non-available?

If you have book and page or recording information of that mortgage, state that.Then give the settlement agent/closer, a closing letter of instructions, state that the payoff as of settlement determines the amount to subtract from the purchase price and to subtract arranged financing to give notice of amounts required to close.

If you pick nice round monthly interest amounts, you add the interest to the debt, then you subtract the payments from the debt and you have the new balance.

In my investing radius, I look for 15% or more after subtracting 10% for management, 10% for repairs and capex and 10% for vacancy. 

I try to look for at least $100/month cash flow PER DOOR which should be $800 per month for 8 units minimum after expenses, taxes and debt service are subtracted from gross rents. so maybe the price is too high or the terms of the loan are too steep.

If entire net Sch C is allowed for QBI, but an S-Corp has to establish and subtract a reasonable salary for QBI purposes - this suddenly puts S-Corp at a substantial DISadvantage against Sch C. 

Let us say my total monthly expenses including debt service, insurance, property taxes, maintenance reserve plus accounting for and allowing for no occupancy then taking the expected earnings per month and subtracting my total monthly expenses should I then realize 1% over and above all of that on a per month basis ?

You'll need to subtract a min $20 per month servicing, plus $200 to $500 for due diligence costs. 

IF you are able to utilize the $15,000 as a deduction, you would subtract it from the $100,000 in income.

     I understand that you can subtract from your tax burden on a rental property using depreciation.