These programs offer options for less money down and in some cases DPA - Down payment assistance.As a banker for over 18+ years I am very skeptical when I hear a new name in the business only because its become tougher to lend with all of the new laws and credit/insurance requirements and regulations.  

The cost associated with insurance for not having 20% is peanuts compared to what you potentially can do leveraging your down payment. 

In this type of situation, they want low interest rate with low down payment also.

Low or no down, seller financing and low or no interest with a balloon payment later is the holy grail (location, building condition, market also matter but it sounds like you have all that).

@Tonya EnglishWithout a clear understanding of what this company does (or more accurately, does not do), the payment seems excessive compared to other services in the market."

I financed this property using down payment funds from 403B and a local commercial bank.

If the other two parties want to flip a house maybe they can do just that as partners and then sell you the house which you can buy with a primary home loan with low down payment.

I think it was for down payment and closing costs.

What would stop him from just not coming back to finish once he gets the last payment from you?

I'd send out 500 at a time, using a different mailer/method weekly.