Albeit it would take me four extra years to pay off the house.

You could invest in syndications if you are accredited or you could just park extra cash in index funds until you have the time to at least side hustle real estate correctly.

Provide extras - the ultra-personal touch.I just love when people try to super overcharge for their services.

1) Do you put the extra rent and deposit in escrow?

Unless we were asked and were being paid extra , we never replaced the pipe going into the tank from the house . 

Of course it sounds good as extra income but as I am looking it does sound like a headache and not appraising well.

Now every week that passes, I'm paying extra to keep my rate in.

The goal is to have paid off properties to pay my parents extra income in retirement. 

I cannot see how build two, say, 1200 sq ft houses with two roofs, two foundations, presumable about 25-30% more windows and siding is going to be cheaper a duplex that might have a little extra fireblocking and soundproofing.Now, maybe your GC is thinking that detached homes tend to get higher rent than comparably sized and finished duplexes.  

If it brings enough to cover taxes, interest, legal fees and auction expenses, plus some extra, the people with redemption rights share the "extra."