1) The document describes several interfaces and classes related to WPF and XAML such as IInputElement, IAnimatable, and DependencyObject.
2) It includes visual elements like UIElement, FrameworkElement, Control, and Panel as well as non-visual classes like Binding, CollectionView, and DataTemplate.
3) The hierarchy shows parent-child relationships between classes, with FrameworkElement as a base class for elements like Button and TextBox and Panel as a base for layout containers like Grid and StackPanel.