Hi Jason, For conventional loans concerning rental properties reported on your PERSONAL tax returns, underwriters will calculate your net rental income based on your Schedule E from your most recent tax return (using Fannie Mae form 1038), depreciation and depletion can be added back in to offset the expenses of the property.  

If a loan via a bank requires the terms to be conventional (5% down), FHA (3.5% down), etc.

You can speak to the lenders you are talking with about their debt to income etc. if you are getting conventional loan they will take that into consideration, if you go with a DSCR loan they look more at the metrics and financials of the property.

Pried open my back, wooden fence    b.

Regular maintenance of the wood (staining and sealing) will prevent weather-related damage and prolong its life.Fencing: The wooden fence offers privacy and security.

You can look at individual loans (conventional or DSCR) or as a portfolio.

Conventional financing for fractional ownership---who is gone mainstream with this type of financing?

You can put a little as 5% down payment for conventional or 3.5% for FHA.Alternative way, is to acquire the 2nd property as an investment property with conventional, while putting 15%-25% down payment.

All 16 units would have to remain on same lot/deed forever (so in terms of value, I can’t capitalize on the duplexes being sold to conventional non commercial buyer) think financially it would be nice to phase it out one duplex at a time.

Don't be discouraged if there is a lot of push back from sellers or agents at first, many of them aren't familiar with seller finance deals or have situations that can't be solved with seller financing (for example, as was mentioned above, they may need a more conventional offer to pay off their house and buy another one).