You're going to have to get some equipment together, it shouldn't be too hard. Anything metallic equipped on a character causes them to have "Paralyze" permanently set in battle.

I go with this setup:

Cecil: GreatBow and Thunder Arrows, Twist Headband, Kenpogi and Ruby Ring
Cid: Wooden Mallet, Twist Headband, Kenpogi and Ruby Ring
Yang: Whatever claws you want, Twist Headband, Kenpogi and Ruby Ring
Tellah: No changes, but put a Ruby Ring on him, cuz Iron and Mythril Rings are no good

Also, you should stock up on Mythril Weapons and Armor cuz you'll need them later. This is gonna be expensive...I hope you have a lot of money, but I guess with your cheats you shouldn't need too much in the way of weapons to beat the Dark Elf.