I like to try to correlate roles in different kinds of trios. I am very familiar with Freudian Trio. I think there is a way to compare. When ecah psycholgical force goes out of balence they may form the trio. The id has personal instinctual drives. It can be the leader who has troublsome plans. The superego has drives to follow solcial norms. It can be the complainer, who will do anything the leader says. The id and superego are soposed to have conflict with eachother. It is the ego's job to reconsile them and cause a peaceful balence. It can be the idiot, who is too oblivious to stop the disasterous collaboration of the other two.
I have been a bigger fan of the number four. I wonder whether there is a new role that may be added. A good choice is a very excited character. It can get crazy enough to cause all sorts of trouble. This new role can be called the loony. It is the opposite of the calm or helpless ego.
On Disney Heroes Battle Mode, the friendship between King Triton and Hank & Dory, sort of forms a comic trio, with King Triton as the schemer, Dory as the follower and Hank as the powerless.