Cheats:
After Verse 3 of Chapter 2, there are three telephones in the plaza. The phone by the stairs is to input weapon codes, the phone on the right is for accessory codes, the phone at the far end is to unlock characters. You will also need a required amount of halos to enter these.

UP, UP, UP, UP, DOWN, DOWN, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, L2 - Bangle of Time (Accessory) / 3 Million Halos
UP, UP, UP, UP, DOWN, DOWN, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, TRIANGLE - Bazillions (Weapon) / 1 Million Halos
UP, UP, UP, UP, DOWN, DOWN, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, R2 - Climax Bracelet (Accessory) / 5 Million Halos
UP, UP, UP, UP, DOWN, DOWN, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, R1 - Eternal Testimony (Accessory) / 2 Million Halos
UP, UP, UP, UP, DOWN, DOWN, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, CIRCLE - Jeanne (Character) / 1 Million Halos
UP, UP, UP, UP, DOWN, DOWN, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, SQUARE - Little Zero (Character) / 5 Million Halos
UP, UP, UP, UP, DOWN, DOWN, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, X - Pillow Talk (Weapon) / 1 Million Halos
UP, UP, UP, UP, DOWN, DOWN, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, L1 - Rodin (Weapon) / 5 Million Halos