The Monster name cheat is bogus. You have all the characters when you first start the game. My name on there is JIMBO and I have all the characters. It may be due to all caps but that shouldn't affect it.
P.S. Is there any way to change the view to 3rd person?
Hey people, I only just bought the game and I submitted my name instead of the standard MITCHELL as MONSTER and found that when I started I had the entire inventory of charaters already at my disposal for use!!!!!!!!
However, I am not sure if this was a fluke or due to something else I did, but anyway enter your name as MONSTER in capitals and you will get all charaters.
P.s not sure if it works in lower case though! Let me know if it is bogus.