Try sampling at 6mo and look for moisture, fuel, and oxidation. That will tell you if you can go further. Sample after the winter into early spring. That will be the time you have the greatest chance for condensation.
Short 2 miles trips do more harm to a vehicle than say 100 miles daily. What happens is the engine never really warms up to normal operating temps and condensation in the engine and the exhaust system never have a chance to dissipate. Letting it idle for 15 minutes will do little to alleviate this and might just add to it.
But I have a car that is driven less than this and for 10 yrs I have only changed oil annually in the spring and use Amsoil 5W-30 synthetic. Some will cringe but I have actually forgotten to change the oil for 2 yrs on at least 2 occasions. The only reason I for this it that I rarely drive that car myself, its there for someone else to grocery shop and go to church with so I always put off doing it. I checked them mileage since I changed it this May, about 950 miles. Never had any problems, but the body is starting to show signs of rust.
So, I am going on 11 yrs at 1/yr, depending on the type of vehicle I don't see why it would not work for you annually.
Analysis is indeed the key. 1 year should be OK. I had a Toyota truck that I sold, but I put maybe 1000 miles on in two years. I changed the oil (Amsoil Series 2000 20W-50) once in 2 years.
You really should get the car out on the open road for a good blast every week or two though.