Your list looks good. I'd prioritize water pump and oil change. The engine mount is probably worn out and it is easier to access a couple of the water pump bolts with the mount removed, so might as well do both together. (Don't support the engine with a jack in the center of the oil pan.)
Does the coolant tank plastic look yellow? -aged plastic ready to crack.
Spark plugs: When I replace them, I replace the spark plug tubes if there is any sign of an oil leak. Clean and inspect the coils for cracks and replace the rubber coil boots if they look degraded.
The vacuum tubing under the intake is going to be brittle. Chances are that it will crack or come apart when you do the AOS. Be gentle or plan to replace it.
What you have written so far shows that you have more awareness than most first time 986 buyers. Everything you need to do to your car has been documented here many times and Youtube videos are great for seeing where other people have made mistakes. Don't hesitate to ask stupid questions.
Many of us have extra parts that aren't listed for sale. Ask if you need any used parts
Boxster and Cayman Parts for Sale or Wanted - 986 Forum - The Community for Porsche Boxster & Cayman Owners and go to eBay if you want it in a hurry.
Enjoy your new car!