Team Leader: Captain America. "Okay, people. I want to secure this building as our base of operations. I want defense points with overlapping lines of sight over all potential entry points. I want a fortified safe room in a central area that will provide supplies to the defense points. I want walls removed to provide rapid travel between the defense points, and I want gates that can close these routes if any defense point is overran. I want a bacon cheeseburger. Those things are delicious. You, stand over there and pretend to patrol the perimeter because you look like you're bored and you need something to do. You, kneel and whimper and make "moe">Bambi eyes for the cameras because the audience loves that in this kind of show. You, shut off that damned DS thing, we have a zombie apocalypse to deal with. You'll take orders from me because I have a flag on my crotch. Let's go!"
Brawler: Iji. She may not look like much but with maxed out strength she can kick a zombie across a four-lane highway, and her nanites and shielding can protect against infection. She doesn't have any kind of fighting technique but neither do the zombies. Brute force will be enough. And as we would prefer not to allow the zombies to get within brawling range in the first place, it helps the team that she has infinite shotgun ammo.
Weapons Expert: Bill from Left 4 Dead. Military combat veteran and zombie combat veteran. He's done this shit before, knows what the team needs, and knows how to keep the team's gear in working order. Perhaps he is too obvious a choice.
Brains: Indiana Jones. The most badass history professor in history, with experience in combat and dealing with the paranormal. He would make a good backup team leader or brawler, and the fact that he drank from the Holy Grail may become plotworthy.
Medic: Dr. Beverly Crusher. She carries around a satchel of 24th-century medical equipment, is a decent shot with a phaser if we need an extra gun, and is smart enough to whip up a cure for the infection during the commercial break. She also has a personal motivation because her smartass kid caused the zombie outbreak with one of his science experiments. I might have preferred the EMH for its invulnerability to zombification but we wouldn't have the infrastructure to support it after the apocalypse.
Speed Fighter: Duncan Macleod of the clan Macleod. He is an immortal swordsman who can only be killed by decapitation and who has centuries of experience decapitating other highly experienced immortal swordsmen. Not only is a zombie fight going to be tee-ball practice for him, but his inability to die should prevent him from becoming the walking dead. If it doesn't, it would be trouble for the team but we know how to kill him.
Mascot: Enforcer from XEvil, the Lego robot whose performance at the MIT robotics fair resulted in the machine being condemned to Hell. Whoever is in charge of such matters was impressed enough to waive the rule about needing a soul. The robot can shred/disintegrate anything it touches, so why do we use it as a Mascot and not in a combat role? We're not crazy enough to turn that thing on! It stands as a totem outside the door of our safe room, silent… until we really need it.
Guy Who Dies First: Kolchak. He is a journalist who was investigating all kinds of spooky stuff decades before Scully met Mulder. He could easily get in over his head on this sort of thing, and killing the comic-relief character is a time-honored tradition in horror shows. He was selected in honor of being one of the last mass-market fictional characters to run up against an old-fashioned zombie.
ain't overpowered because of no eldrazi