Team Captain: Raistlin Majere / Dragonlance
Why you might ask? Simply put master of past and present. He challenged the dark queen and only lost because he sacrificed himself so his world wouldn't fall into darkness. Always ten steps ahead of everyone and has no fear. He is a genius and likes to manipulate events from the shadows so you barely know he is there. As long as your loyal to him he always will have your back protected, but screw him over and well then you become expendable. His plans don't fail.
1st Round Pick: Deadpool / Marvel Comics
An unkillable killing machine. I like those odds. Plus wouldn't it be fun to watch the interactions between Raistlin and him. Plus we need a prankster and comic relief.
2nd Round Pick: Freddy Kruger / Elm Street Series
I don't think people will like this one but here is why I do. OK he's the master of the dream world so while the enemy sleeps Kruger takes them down period. So now you have your enemies being slain 24/7. Plus if they find out about him they try to stay awake which in turn makes them weaker.
3rd Round Pick: Felicity Smoke / Arrow
Pick 3 is my tech expert. Come on she is Oliver's right hand and she has solved all of the atom's suit issues making them both into the heroes their city deserves. She would not fail this team. Plus she has a habit of being networked with other heroes that she can just call up if the need arrives.