For the storm you could roll to see if a player is struck at the beginning of each player's turn and make it a wizard's lightning spell attack on a random opposition player (or one of that teams own players but always the same so as both teams are equally threatened).
Also there is a problem with equating highest AV with "most metal". Compare Mummies (helmet and shoulder pads) and Wights (head to foot armour). The one who clearly has the most metal also has the least armour.
I hope you are planning on more than 2 hours per match in your tourney
Just keep in mind that most normal games with rookie teams take 2 hours to play. If you are adding special rules people are going to take longer. Some people can't even finish a normal game in 2 hours *coughOldManMonkeycough*
[Oh, and you don't mean tenacious do you? That's "Holding together, cohesive; tough; not easily pulled in pieces or broken". Although a Zombie that's still coming after you terminator style with only one arm, a head and a torso left would be quite funny.]