By renting out the other side, you'll have far less to pay towards the mortgage every month.This allows you to control a more expensive asset for less than it would otherwise.For example, buying a single family home for $350k with a 10% down payment and a 5% interest rate would give you a PITI of roughly $2,321/mo. 

The added equity is the same money, with the same face value, as if it were still in your control in your bank. 

I would suggest you evaluate programs that offer checkbook control such as the IRA LLC or Solo 401(k). 

Plus, if/when rent control becomes real here......I'll make a million $ on paper over night almost.

Are you under rent control?

I was just wondering what banks would think of my controlling the day-to-day of the property and a parter only being passively involved past the mortgage signature with no real skin in the game.

You have no control over rental restrictions 

I wonder how the mini-split would perform as a heating device for cold places, like Detroit.Anyone with experience?

This is probably my major complaint as this is totally controllable.

(c) A water supply approved under applicable law, which is:(1) Under the control of the tenant or landlord and is capable of producing hot and cold running water;(2) Furnished to appropriate fixtures; and(3) Connected to a sewage disposal system approved under applicable law and maintained in good working order to the extent that the system can be controlled by the landlord.