Well, it's not a straightforward yes. Some DC movies are direct adaptations of comic stories, but others take elements from multiple comics or even deviate significantly to offer a fresh take on the DC universe.
Yes, there are. However, their availability might vary depending on your location and the specific comic publishers. Sometimes, limited editions or special releases of All Might comics can be harder to come by.
Not all DC Comics novels are suitable for all ages. Some, like 'The Dark Knight Returns', have a darker and more violent tone that might not be appropriate for very young readers. However, there are also many that are family - friendly, like some of the Superman stories.