Tools of Characterization
You don’t need us to tell you that Daniel, Reuven, David, and Isaac are not just characters in The Chosen, but also Biblical figures. With long and confusing histories. No doubt, Chaim Potok knows his Biblical characters, and has very personal reasons for naming his characters. But, long and confusing histories are probably not what you want, so we’ll keep it simple.
Davey Cantor (one of the minor characters) is a good place to start. We’ll skip the "Davey" and get right to the "Cantor." In Judaism, the cantor is the person who sings and leads songs. Singing, or chanting, or repeating are also ways of bringing news. And that’s what Davey does. The news is usually bad. They don’t call him "gloom and doom Davey" for nothing.
He’s the first one to tell Reuven that Danny and his teammates are "murderers." He says it over, and over, and over. He chants it, or cants it, as the case may be. Remember, Davey also breaks the news to everybody at Reuven’s yeshiva that President Roosevelt has died of a cerebral hemorrhage. Reuven says of that moment, "It was like God dying." Davey is also kind of running joke among his schoolmates. But, just they wait – when he grows up and becomes a real cantor, he’ll get to blow one of these: a shofar, or ram’s horn, an instrument used in Jewish prayer ceremonies.
Saunders is also an interesting name. We learn that, on Ellis Island, Rabbi Saunders gave his name as "Senders," which was somehow recorded as "Saunders." We wouldn’t expect a man like the Reb to just give up his name, but he knew that he needed to go with the flow to help his community make it in America. Senders sounds like it means "people who send." In the case of Reb Saunders, he was sending himself and his followers to America.
Reuven’s clothing is much less traditional than Danny’s, but both of them stand out as Jewish boys. Danny’s clothing is so traditional he’s afraid it will interfere with his career. Moreover, Danny wants to choose his fashion identity on his own. Which characterizes him as strong and independent.