So I have this headcanon that miitopia god had to convince each character to join the team. In order to do so he asked what did their hearts desire and had to either promise a reward or explain that they can achieve their goals through this journey.
Each team member's specific reasons:
I Want Die - money to pay for his medical bills. He lives in eternal pain, but because he is just an old man he cannot afford treatment. All he can feel is agony, so he is very cynical and straight up asked for a fortune.
Mr. Bean - when god asked him what he desires, the answer was "Bean." So that is what he gonna get in reward. Now will he be pleased or disappointed with it is hard to tell. He's an enigma for sure.
Chat - to merge into one being and become fully human. Their body is artificial and doesn't look quite right or work properly. That's why they hide behind the mask and obsess over robes.
Goofy - to start the revolution and overthrow Mikey Mouse. He lived in his shadow for far too long! But for that he needs to get real battle experience and right connections and to become stronger, much stronger. So this adventure is a great opportunity for him.
Cupcake - to be able to murder things and not get arrested for it. She was on a verge of becoming a hitman when god met her. Miitopia is full of monsters, and hero is a better profession choice in god's opinion.
Gilbert - to become favorite child. It's kinda obvious it's not going to happen, but god gave him a chance anyway.
Dread - to do something right at least once in their life and never have any regrets about it. Also they are like the only one actually concerned about saving the world from dark lord.
Obama - to be eternal president (he doesn't know he already is in our hearts) /j
Jefferson - to have family again. He doesn't remember that well his original family of penglings because he was kidnapped by Robin in such a young age. But then Robin became his new family. He's even gotten a mechanical brother at some point. He was so happy until Robo-Jeff died in an 'accident' and Robin went away with an alien centaur guy. He was left alone and didn't know what to do because he was only a child. So he just sat there and cried.
John - to get friends. All his life he was rejected by people around him because of his weird look, social awkwardness and connection to the magic. However despite the fact that he was literally thrown in a volcano as a sacrifice John didn't become resentful and his heart is still open and longs for a companionship.
Sorry if there are any mistakes, English is not my first language.