If we added a mortgage office, our customers could buy a new home turn key, just from our office. 

For that, it doesn't mean I wouldn't buy it or make a market for it.

OLD stock yazoo clay and houses that originally were built as cheap as you can build .. of course not all but a vast majority of what you folks buy for cash flow rentals.then  on top of that a VERY tough tenant base and that market can really frustrate folks I owned over 200 of those and the happiest day of my life was when my partners bought me out for 4k a door.. done gone and good luck lOL

I am looking to buy a turnkey property (SFH 3-bedroom) in Florida for cash flow.

Is he buying it from you or is it a gift? 

The cost for material would be $15-20 on the low end and that would leave only $$25-30 to go to the store buy a door knob come back and install.

My idea is to buy a house and rent it out, so it can pay for itself while I live in a family-owned house.Would you recommend buying a house in Orlando right now?

First 10 years I/O and fully amortized for 20 years thereafter..If it's full income verification, strong credit and a lower LTV you should be able to get there with a mild buy down..Check in with @Joseph Chiofalo for a quick second look.

In this type of scenario, is it still worth buying the duplex with one unit owner occupied?

I have a deal all signed to buy a home sub2 in Pueblo Colorado, but I realized the mortgage is a FHA loan.