Unlock All hidden wrestlers:
Goto the edit wrestler option and select the name entry section. If you submit  ALL for  the Nickname, STYLE for the First Name, and CLEAR for the Last Name. After this is done  set Exchange to OFF, Middle to SPACE (the square icon), and lastly push Start. When you push B until you return to the main menu all wrestlers will now be playable. Here is a list of the Wrestlers that are unlocked.

The Runner KLEEBO HBK - Shawn Micheals
Slim Jim Mr. Mann  -  Macho Man Randy Savage
 The Lastman OMEGA  - Mick Foley
Godfather MADMAN MUSKI - Vince McMahon
Dragon Soldier YASU OHHASHI - Kaz Hayashi
Shining Dragon AZTECA DRAGON - Ultimo Dragon
Darkman KILLA KALANI - Ric Flair

Get Stone Cold's music:
When you go to the edit wrestler option and go to skills you can select theme music by choosing Viper. If you push R you will hear Stone Cold's music.