Press L when near the apron in a Hardcore Match to get a weapon. Press L and Down to place it inside the ring.
The Rock - Win the RAW story mode five times with Chris Jericho.
The Big Show - Win the Smackdown story mode five times with The Undertaker.
Hulk Hogan - Beat season mode with The Rock.
First, win all the original show your character is from. Then you will be able to play on the other show, Smackdown or RAW, facing the characters from that particular one.
To unlock The Rock, complete story mode with every character.