for Olcadan, you don't have to beat him, if you engage in 575 battles he is automatically unlocked. I have unlocked everything single standard character and am currently working on unlocking all of the bonus characters. I also have 10 custom characters and have unlocked all of the "jobs"
I'm a big DBZ fan. Some of my favorite characters are Vegeta, Cell, Janemba and definately Trunks. I am a moderator for the Budokai Tenkaichi forums.