Sorry no "official" document. Some of this is strategic.
1) For the rear diff oil change, I told them that my rear diff was making noise going around corners (it was, but it wasn't bad) - they changed diff oil.
2) Spark plugs I'm not sure why they did them so early. The owner's manual says 37,000 miles
I think the "inspection" which my car said was due is a top-bottom inspection but my service note didn't say what they did or inspected. Good luck with your service