Any ol' programmer or business kid used to be able to form a start up and get it funded and use this is afford expensive housing and hire those who can.

This one with my pro forma calculations has a $200/ month cash flow so I can see why it's may have a tougher time moving. 

There are only 3 reasons to form a partnership. 

Since it would take 12 to 36 months to build the property anyway you might be able to get a lender to finance based off of the pro forma value of the after completed duplex at a substantial rent premium to whatever your underwriting today.As mentioned about $96 psf cost to build seems wildly low considering the market supply issues on materials and inflated demand do to low cost of capital and now congressional fiscal stimulus and tax programs.

At least now you know how the whole process of buying a property looks like and that closing costs are a lot more than what Roofstock assumes in their pro forma calculation.

I then went a step further to send him the pro forma I put together that clearly states some of observations I've made that I don't think he is considering and included a personal message inside the pro forma, asking that he could pass it on for the seller to see... within a few minutes he responded with a short "No - Our Counter Stands."

Of course, with all things, the answers to all these matters will depend on the circumstances.California tends to have more laws on the books and requirements and restrictions that it can be a good idea to form a CA LLC for out of state property so that you as a CA resident are covered, and to try to have your contracts fall under the purview of CA courts.

@Anthony Harris, would you like to be the one to try out a seemingly untried strategy:- showing them realistic/conservative pro forma predictions (rather than best/optimistic ones)?...

My main caution at the moment is to get up-to-speed on NYS laws and be wary of purchasing occupied properties without verifiable pro forma. 

In Washington state we sometimes transfer in or out of an LLC and simply write "mere change of Identity" on the tax form. As