A 3326 trailer is going to weigh well over 4000 pounds when packed up and ready to camp. In the context of a 4000 pound trailer, adding or subtracting 20 pounds in weight is absolutely meaningless. I don't mean to be unkind, but your question is typical of the feeling that there is a magic threshold, and if you are under it by even one pound you are golden, but if you are over by even one pound, the world will end. It just isn't so.
I would go to
http://www.ford.com/towingguides/ and get the real scoop for your vehicle, engine, and year. It looks to me like the Edge has
at best a rated towing capacity of 3500 pounds, and only if it has the correct engine, and a factory-installed tow package. But the tow package includes only a Class-2 hitch receiver (you need Class 3 minimum) and a 4-way trailer electrical connector and wire harness (you need 7-way ). The Edge is not an adequate tow vehicle on either count. Don't do it!
My daughter has a Ford Edge, and it is a wonderful soccer-Mom car for her, especially with the 4WD (she lives in snowy Maine). But I wouldn't tow a TM with it. I think it might kill me.
I don't know how big your boat is, but if you put the TM behind the F350, you would be golden on that half of the equation. What does the boat weigh?
Could the Edge handle it? Could you trade the F350 plus the Edge for a pair of F150's? (Just kidding - again, I don't mean to be unkind.)
Bill