When you use a QuadBatch directly, the images you are adding above in the code are never actually added as children of a parent. A QuadBatch optimizes the shared texture and raw vertex data that gets used with each call to quadbatch.addImage but the image instances are never part of the display list.
This is why if you look at the current implementation of QuadBatch, its getBounds and its inherited hitTest function (which is used for touch processing) is strictly based on the copied vertex data from each of the images you gave it.
You would actually have to subclass the existing QuadBatch and override and implement some specialized hitTest() function just to tell you more specifics, but I don't think you are really going to be able to easily map it to some 'child image' that you are expecting.
If you need unique image hit testing you might have to drop the idea of using a Quadbatch directly and using the images in the display list, or maybe something like the QuadTreeSprite will offer something useful if you need optimized high volume sprite rendering... http://forum.starling-framework.org/topic/quadtreesprite-extension#post-27177