Dominant Se: Improv is Jack’s comfort zone. He can usually see when something isn’t working the way it needs to be and can accommodate. He can always back up his decisions with reasons and fi someone else doesn’t have proof to back up their arguments, he won’t believe them. Jack wants to do things. Where David is thinking “No, we’ve got to think about this!” Jack is thinking, “Let’s just do it,” and jumps into action without further ado. He loves action, and willingly puts himself in the middle of fights to protect his friends or get what he wants. He doesn’t always think about the consequences of his actions, and his spontaneity often gets him into trouble.
Auxiliary Ti: Jack talks, and he talks very much, and very well. He likes to make fun of people’s illogic, and can easily think of out-of-the-box solutions for surprising situations. At the same time, he doesn’t really follow the same rules of logic as other people, and tends to bend the concepts a bit to fit what he needs. He doesn’t always have the focus to keep his life in as much order as he would like (he dreams of Sante Fe, talks about it, but doesn’t plan ahead enough to make it a reality).
Tertiary Fe: Jack isn’t hesitant in asking people exactly how they feel about him. He’s a bit of a flirt and cares what people think of him (all that talk about “let them laugh in my face I don’t care!” is just talk). He is compassionate and caring towards the other boys, and willingly sacrifices his dream of going to Santa Fe in order to stay with them. When Jack sees the danger of new developments that scare him, particularly the police and Pulitzer’s threats against the newsies, he backs down from his formerly firm stance and gives in to the threat. Jack has a charisma that appeals to others and allows him to motivate them to action (ethos arguments).
Inferior Ni: Jack Kelly is a dreamer –we all know it. His desire to go to Sante Fe is the underlying motivation that keeps him going any time that he gets down. When he meets David’s family, he leaves feeling slightly saddened because he doesn’t have a family of his own, but then he immediately launches into his dreams of Sante Fe. Even though Jack knows what he wants long term, he doesn’t really make plans for how to get there, so much as dream about it. He has a million ideas and finds clever ways to avoid the police and bend the rules. Jack often has so many ideas that he can’t come to conclusions (he relies on David for conclusions during the strike). He instinctively sees potential in David within seconds of meeting him, and immediately sets course to help him realise that potential.
I’ve gotten some requests for other Newsies characters, but I’m not in the mood for musicals, so I’m not going to write up full typings for each of them, but David is an ISTJ.