All hidden wrestlers:
Select "Edit Wrestler", then choose the "Name Entry" option. Enter ALL for "Nickname", STYLE for "First Name", and CLEAR for "Last Name". Then, set "Exchange" to "Off", "Middle" to "Space" (Square icon), and press Start. Press B until you return to the main menu. All wrestlers will now be unlocked.

Hidden wrestlers
The following are found after unlocking all the wrestlers.

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

Replacement moves
Body Clutch Suplex: Rock bottom
Deep Freeze: Stunner
Arm Hold w/Headlock: Crossface
2x Arm Facebuster: Pedigree
Mouth Claw: Mandible Claw