this is a great topic! now before i go on, my comic is way too weird or controversial a la south park, I dont mean to offend anybody (well kind of) but remember this is show business and its purely done for the shock value nothing else.
Tommy he has been a millionaire all his life, his biggest fear is to lose all his properties
Billy is a street wise guy, his biggest fear is being defeated by someone weaker than him (a girl)
Cyan never met a black person in his life (he is from Siberia) and is super racist (unbeknownst to him until he meets a black person) his worst fear is to lose his prized possesions to a black dude (that story will happen in issue 5)
Bud has an alcoholism and gambling problem, his biggest fear is to acknowledge he has a problem
Kenji his biggest fear is being a poor karate student, and unworthy of his linage, also that his sister may be in love with making his celibate dedication end
Carlos being found by the NSA, paranoic as hell