Unlock Shion's Vector Costume:
To begin with Shion's Vector costume from Xenosaga: Episode 2 start a new game and then load a completed saved game file from Xenosaga: Episode 2 on your memory card.

Unlock Allen Swimsuit and Chaos Flawless Costumes:
Successfully complete and save the game then load the cleared saved game file.

Ziggy Swimsuit Costume:
Successfully complete the Advanced Hakox levels.