Use Reiko Hinomoto, and play with her until she becomes the champion. Then,use Evil Rose and BEAT Reiko. Take the championship title from her. Then win the reward match against Rowdy Reiko.

You must get 9,000 cash then go get the audio set in the shop.

You must get 8,000 cash then go get the camera in the shop.

From the Locker Room, go to the photo shoot mode with all of the characters. It will unlock and become available in the shop under Edit Costume.

When you play as any default character in their swinsuits for several matches, the suits themselves will eventually become available for purchase. They'll go for $9,000 for all the other characters.