I see a lot of value in aggressively paying down the mortgage with the excess cash flow and personal income.

The laminate is also excessive IMO. $7 a sq ft installed but it doesn't list material price.

Maybe your expenses will get covered by the other rents, but unlikely you’ll have excess cash.

BUT any raise I get, excess money from the kids moving from private school to public school when they hit kindergarten and other “found money” goes straight into a rental down payment fund.

So excessive water usage is a double edge sword.

If you had them drafted by an attorney (probably not since it's at usurious interest rates but you never know), there could be a provision in there for what happens if the loan is deemed to be usurious (i.e. interest rate gets automatically reduced to lawful rate and excessive interest collected gets applied towards unpaid balance of principal). 

@Brent Coombs  Absolutely using sold comps, maybe to the point of excess sometimes...

However if they just want to invest excess capital a house flipping business is NOT a good idea.

When combined with the appropriate use of leverage, you can supercharge your returns in excess of 20% right here in the local market.  

So in all cases but one the spread is greater than 3%, and in that case (using higher-interest bridge debt) we plan to refinance into lower cost debt by year 3 which will then create a spread in excess of 3%.Unfortunately buying commercial income property (includes multifamily) requires very sophisticated financial analysis and there are no shortcuts or rules of thumb that will give you the complete picture.