A few quick answers:0. Download and install Madgod's Cosmic Forge. It will give you the conclusive answer of what items may occur and where. I'm sorry I don't have an immediate link for you, but search the site and you'll find one.
1. I must defer this one to someone else.
2. At least in Bane (Wiz6), each step, turn, or other carriage return while one is not in combat or viewing the character screens is 1 minute, so it is almost always faster to walk back to a fountain than to rest for 480 minutes/key strokes. My characters never sleep.
3. This is a perfect example of a Cosmic Forge question: I boot up the ol' Forge, click on "Item List," page down to "Locate Person," double-click to pull up the item editor screen for this item, and down in the lower right is a list of all of the treasures in which this item occurs. You are probably thinking of its occurence in a chest in Old City: "loot entry" 31, where it is a guaranteed item.
4. No idea. (On the other hand, I've never heard of T'shober defeating ANYONE, and I don't think Magna Dane is even available as an NPC encounter (as opposed to the T'rang Queen and the Gorn King, both of whom can be killed in their original (or only - for the Queen) locations. My own personal strategy for minimizing deaths is to delay, as long as reasonably possible, the release of npcs that don't start out roaming: T'shober, Shritis, Rodan, etc.
5. What is "good" depends on your party's make up, to some extent. Items in the Crusaders Chest are all set, so don't worry about that. The Giant Cave Chest has a selection of items, so it is worth saving and reloading. In my personal "shopping list," I save and reload to get a Spear+2 from Capt. Boerigard (not for CODS, but for importing to W8: this is easily one of the best - or the best - importable weapon), an Amulet of Airs from the Old City Key Chest, a Stave of Silence in Orkogre Castle, Silver Gloves or Sollerets beneath Nyctalinth, a haunting stick in the Witch's Cave, a Faerie Cap or Chaimail +2 from the Chrome Key Chest and the Deadly Coffers Chest, and a Mana Stone from the Book of Immortals Chest, among other things. (I have a very long shopping list.) Pandoras Wand IS available in the underground temple in Munkharama: it's a possible treasure in the chest with the Key of Good Keep.
I hope that was helpful.