Help with co wholesaling PLEASE!!!

[Julian Lyons]

Okay my name is Julian Lyons. Hello to all and thanks for any answers I get. 

I was doing some good old craigslist cold calling and I came across a buddy of mine who has a nice house under contract for the low($). I got an options contract sent over to him, we got it signed so boom. I start marketing get a couple buyers lined up but one day this realtor called me with a contract from his buyer. So in this A>B>C>D>E transaction. 

A is original seller who wants 12k

B is my buddy I have an options contract with for 16.5k

C is me 

D is this realtor guy with the buyer at 22k net to Seller(s)

E is the end cash buyer who has agreed to compensate the realtor and pay 22k

I have the A>B contract 

The B>C options contract

And a The C>E contract sent to me by the seller. 

What documents am I missing to send this over to the title company??? Do I sign an Assignment of contract with the end buyer. That would put him in the spot of my options contract. Or do I have my partner sign an assignment of contract with the end buyer??? I just need to know all the signed documents I need to get this co-wholesale CLOSED. 

Thanks for reading and again, I greatly appreciate any and all answers!