1) ParentZone property can accept values from INDockZone interface type which is implemented indirectly from NDockingPanelHost. You can convert the value of ParentZone property to NDockingPanelHost using "as" which should give you the actual panel that hosts the docking panel.
In NDcokManager.RootZone.Children you can find only the children for that level. You can have another NDockZone as a child of RootZone which on other hand has its own children.
The docking framework has tree-like structure.
2) You can iterate through NDockManager.Panels collection which holds reference to all NDockingPanels that
are registered by the the docking structure, and check their DockState property for AutoHide state.
3) To set a NDockingPanel in AutoHide state you can call AutoHide method of the panel.
I hope this helps.
Nevron Support Team