The healing factor is Deadpool's largest edge, and it is what will give him the victory.
Red Hood has certain advantages over Deadpool, but the mercenary will make him too angry to use them.
While Hourman has superhuman strength, he's been harmed previously by someone wielding a sword, which will be a concern when he faces Deadpool.
Nightwing doesn't have many weapons with which to severely injure the mercenary. eventually Deadpool will have him.
Stargirl isn't going to let loose against Deadpool, allowing the mercenary to injure her.
Beast Boy would quickly understand that Deadpool's healing factor allows him to let loose.
Deadpool will attack Hawkman's wings, robbing him of the majority of the benefits that flying provides.
Making mistakes and trying to make amends is one of Booster's distinguishing characteristics. That's not going to happen when up against Deadpool.
CYBORG WOULDN'T PICK UP THE PACE UNTIL IT WAS FAR TOO LATE, HANDING THE VICTORY TO DEADPOOL.