Your list looks pretty good. Ditto to what Hung said about having the original engine. Trading them in is quite common and should not send up a red flag.
Don't underestimate the importance of a pre-buy buy a different mechanic than the one who has been maintaining it though. Ask if you can watch or participate in the inspection. If not, then go to another mechanic. That will be very educational! If that plane fails, you'll be much more informed as to what to look for before you proceed with having another one looked at.
If the plane looks good and the annual is approaching, ask the mechanic how much more it will cost to turn it in to an annual BEFORE he puts it back together.
Most owners look at their planes through rose-colored glasses. Can you blame us?

Keep this in mind when considering the answers you get to your questions.