Alternate costumes are activated for characters as follows:

Kasumi
Costume 1: Press A (Blue Ninja Outfit, Hair in a Ribbon)
Costume 1: Press X (Blue Ninja Outfit, Hair in a Braid)
Costume 1: Press Y (Blue Ninja Outfit, Hair Loose)
Costume 1: Press A+ L (same as Costume 1 with A)
Costume 2: Press A (White Ninja Outfit, Hair in a Ribbon)
Costume 2: Press X (White Ninja Outfit, Hair in a Braid)
Costume 2: Press Y (White Ninja Outfit, Hair Loose)
Costume 2: Press A + L (same as Costume 2 with A)
Costume 3: Press A (Schoolgirl Outfit, Hair in a Ribbon)
Costume 3: Press X (Schoolgirl Outfit, Hair in a Braid)
Costume 3: Press Y (Schoolgirl Outfit, Hair Loose)
Costume 3: Press A + L (same as Costume 3 with A)

Hayabusa
Costume 1: Press A (Black Ninja Outfit)
Costume 2: Press A (Black Ninja Outfit with open arms, a mask, and gray boots)
Costume 2: Press X (C2A in White)

Hitomi
Costume 1: Press A (Denim Jacket, White Top, Denim Jeans)
Costume 1: Press X (Gold Top, Denim Jeans, no jacket.)
Costume 2: Press A (White Gi, Black Shirt)

Zack
Costume 1: Press A (Bare Chest, Black Flamed Trunks)
Costume 2: Press A (Purple Silk Jacket, Teal Shirt, White Silk Pants)

Gen Fu
Costume 1: Press A (Black Tunic, White Tiger Stripe Legs and Arms)
Costume 2: Press A (Green Silk Sleeveless Top, Tan Silk Pants, and The Hat.)

Brad
Costume 1: Press A (Black/Scarlet Tank Top, Blue Pants)
Costume 2: Press A (White Gi, Blue Trim)
Costume 2: Press X (Orange Gi, Black Trim)

Tina
Costume 1: Press A (Blue Crop Top, Zebra Pants)
Costume 1: Press X (Green Crop Top, Leopard Pants)
Costume 2: Press A (White Fringed "Cowgirl" Outfit)

Bass
Costume 1: Press A (Black Leather Bikers' Outfit)
Costume 2: Press A (Red Bowling Shirt, Black Pants with Yellow Design, Red Bandanna and Gloves)
Costume 2: Press X (No Shirt, Black Pants with Blue Design, Blue Bandanna and Gloves)

Leon
Costume 1: Press A (Desert Camo Outfit, Black Turban)
Costume 1: Press X (No Shirt, Bandoleer of Shells, Desert Camo Pants)
Costume 2: Press A (Shades, Black Shirt, Red Pants)

Bayman
Costume 1: Press A (Red Beret, Orange Vest, Urban Camo Pants)
Costume 1: Press X (Blue Beret, Black Shirt, Woodland Tiger Stripe Camo Pants)
Costume 2: Press A (Russian Navy Commando Outfit)

Jann Lee
Costume 1: Press A (No Shirt, White Pants with Red Dragon)
Costume 1: Press X (No Shirt, Black Pants with Gold Dragon)
Costume 2: Press A (Purple Kung Fu Outfit with Gold Trim and Sash)
Costume 2: Press X (Gold Kung Fu Outfit with Purple Trim and Sash)

Leifang
Costume 1: Press A (Red Cheongsam with White Design)
Costume 1: Press X (Blue Cheongsam with White Design)
Costume 1: Press Y (White Cheongsam with Gold Design)
Costume 1: Press A + L (Black Cheongsam with Gold/White Design)
Costume 2: Press A (Black Leather Outfit)

Christie
Costume 1: Press A (White Jumpsuit with Teal Trim)
Costume 2: Press A (Purple Pinstripe Business Suit)
Costume 2: Press X (Magenta Pinstripe Business Suit)

Helena
Costume 1: Press A (White, Blue, and Black Opera Outfit with Thigh High Leather Boots)
Costume 2: Press A (White Opera Outfit with Blue Trim)
Costume 2: Press X (Black Opera Outfit with Red Trim)

Hayate
Costume 1: Press A (White Ninja Outfit)
Costume 2: Press A (Red Padded Ninja Outfit)
Costume 2: Press X (Green Padded Ninja Outfit (Same as C2A, but Green)

Ayane
Costume 1: Press A (Purple and Black Ninja Outfit)
Costume 2: Press A (Purple Butterfly Outfit with Yellow Ribbon)
Costume 2: Press X (White Butterfly Outfit with Orange Ribbon)

Ein
Costume 1: Press A (Matrix Look. Black Trenchcoat, Mesh Shirt, Black Leather Pants, Shades.)
Costume 2: Press A (White Gi, Black Belt)