I would be very careful with using 100% leverage in a deal.

Also, always be careful with very long-term residents that are far below market rent, it's very possible there are issues they live with and don't say anything about because they've been there so long and they know their rent is cheap.

I don't care who you are or what you do.

Facebook groups have useful information, but tend to be about 75 percent spam or sham so you have to be careful in there.

Solar id be careful with, it can sometimes cause and create more issues then it solves.

Current building code requirements and local amendments should be considered forrebuilding the fire-damaged portion of the residence.The Engineer shall have no liability to the Owners, or to others for the acts or omissions of theContractor or any other Persons performing work on the project, or failure of the Contractor tocarry out the work in accordance with this letter, except where specifically inspected andapproved by the engineer and discovery of defect is possible within the normal ability or standardof care for the industry.This report is based on a diligent visual inspection of the referenced areas.

If most people do the same, a lot of the scams & spams take care of themselves because there's no audience. 

So be careful and make sure you interview the Expediter and that they have had success in obtaining the Letter of No Objection.As far as evidence that you need to gather, look up your buildings TAX Class.You will find it here: Building Information SearchHere you will see something that looks like this:NOTE that while this is a Dept of Buildings Web Portal, what I have circled in RED is the Department of FINANCE Building Classification.You may not have a CofO, but the Dept of Finance maybe taxing you as a 2 Family.

People who have money may prefer to seller finance but if someone is retiring they most likely don’t care about a higher sales price they want to avoid the riskYou mention ou have a 100% close rate - then why not just buy it was traditional financing if you really want the deal?

Be careful of people offering to help.