Okay so I got it up (gee i hate extracting stuff lol).
Answering the points...
2 - I'm guessing that hiding a parent object will hide all its child objects.
Parent/Child objects are formed by linking which can be visually be seen by moving the parent object or pressing H and checking "display subtree" and finding the object name in the list.
3 - It looks fine for me when I imported it...
It might be your importer or you may have moved it accidentally.