I bought at duplex, 3.5 down, FHA; My mortgage is estimated at 508 per month and the first floor is currently being rented to 650 bucks.

Just remember , it sounds easy , everybody thinks its a quick buck , lots of people are trying to do it . 

The above will get you within a few bucks a month.PMI, which comes with conventional non-FHA mortgages, can vary by lender. 

Cloud, Green Bay, Milwaukee.

Spend the best few hundred bucks you have spent in years.....sit down with a local RE attorney familiar with foreclosures, with your list of questions/assumptions.

My question is, would it be fine to go ahead and push to start the lease on the 1st, so I can get a full month's rent for December, or just let him start it on the 9th and lose out on 9 days rent out of the month (which actually comes out to about 190 bucks)?

Although, it seems like a lot of effort to only make $500 or so bucks a month on a rental, well, at least if you consider that it's a much more active affair than buy/hold REI. 

I always thought duplex is more "bang for your buck" but can see it has its own draw backs. 

You might spend a few bucks more now but when you go to sell it in the future the insured chain of title will save you future expenses and bring top dollar to your future sale

Spend a few hundred bucks, and sit down with a local RE attorney.