Can't go into details on the hunts because i'm in a rush but you'll also need to save a fair bit of LP to unlock the License and 30,000 Gil to buy it.

It only affects items on the equipped character and items ignore vitality so will work 100% if the target is not completley immune. Pheonix downs i believe KO enemies instantly who do not carry the Safety Augment (Entites, Marks Bosses and generally tougher or late game enemies)