Iceman can without a doubt kill Hulk. He is an omega level mutant. Hulk has the strength to resist iceman freezing him into a block of ice, and would probably break it right open. But, iceman can manipulate his control of ice by becoming different phases of water. Thus he could kill the hulk simply by taking the form of vapor, enter hulks body(bloodstream), and freezing his blood.
First, I'm not really sure a PhD really helps in this argument. Anyways, hulk smashing iceman in half would accomplish nothing because physical attacks can't kill iceman. He will simply reform. In fact, hulk could never actually kill iceman for because all of his attacks are physical. But that's not the argument. The argument is that iceman can kill the hulk, which he can, not that the hulk can kill him as you just stated. As the con, you must explain how hulk could possibly not die in a fight with iceman.