This depends on how well you know their tastes and their parents. The John Green books, for example, may have content that a parent objects to. The Hunger Games' demographic is teen girls, actually, though a little older than 14-year-olds. If these kids are readers, the 10-year-olds may have already read the Narnia series. The minecraft set is a GREAT idea because you indicate that this is a personal interest for him.
Check their shelves. You've listed easy-access books the kids might already have. For the teenage boy, if he's a reader, I might recommend some Edgar Rice Burroughs, Jeffrey Overstreet, or Stephen R. Lawhead (The Dragon King trilogy or the Pendragon Cycle are good starters). For the girl, I might recommend Ally Carter. For the fifth grade girl, I might recommend Anne of Green Gables. For the fifth grade boy, I would recommend John Christopher or Orson Scott Card. These are options, as they are all series that are age appropriate and would encourage the kids to read up and out. But again, check their shelves and if their parents have any restrictions or concerns.