Question: How old is Edward?
Answer: It is never stated.
Question: When McClane ejected from the cockpit of the military plane, why didn't Colonel Stewart and his men shoot him while he was in the air? These men deliberately crashed a commercial plane killing innocent civilians and by doing this, it's obvious that they are ruthless, so why wouldn't they try to kill their main enemy when he is at his most vulnerable? (With the weapons the soldiers had, McClane was still in range to be hit.) Can someone explain this for me?
Answer: Because the police were moments away from arriving at the scene. They needed as much time to get away without being tracked. Every moment counts. And a target rocking about a few hundred feet in the air doesn't seem to be such an "easy target".
Question: If Old Man Marley is actually a nice man (and not a "shovel slayer" as Buzz claims) then why does he always give Kevin that cold, creepy stare? After Kevin ran away the first time wouldn't he want to talk to Kevin the next time, to assure him that everything is okay?
Answer: Because he's understandably angry that Kevin's so unreasonably scared of him and assumes the worst in him without even getting a chance to know him. He never gets a chance to talk to him, because he always runs away too quickly. The first time he gives him that stare was when Kevin was watching him shovel from the window. Nobody would like to be stared at like that while doing a simple task.
Answer: Marley appears that way mostly because the audience sees him from Kevin's point of view. Marley is miserable and sad because he is estranged from his family, but we see him as a crotchety, unpleasant person because that is what Kevin believes. Buzz had tainted Kevin's opinion of him by spreading the false stories that a gullible Kevin believed were true.
Answer: As the other response says, the number of years is never stated. Physically, I think he is supposed to look about twenty years old. Bill wants him to start a proper business. None of the adults seem to think that he should be in school.