Hemingway reveals his much about his characters through his use of dialogue and description of their actions and reactions. Readers can make educated assumptions about a character's personality based on these things. Hemingway wanted the reader to be able to formulate his or her own conclusions about his characters, which engrosses the reader that much more into the story. "Less is more" was his philosophy!
To answer your first question, I would not like to see any more information provided in the story because the readers are able to get enough information from the story and characters to obtain the theme and/or meaning.