Structuring of the deal with seller financing

[Jaroslaw Karbowski]

How would you structure a deal with sellers that's willing to provide financing for  three properties located side by side. Sellers looking for some down payment, reasonable  % interest rate and long term financing. All three  homes in need of  some TLC.  2 of them currently rented and one is occupied by the seller.There's a possibility of taking all three homes down and build 6 new townhouses. 

Thank you