First off thanks for your service
For that extended period I would be more aggressive. Skip the 12k service so you get new belts when you come back. Fog the cylinders until it dies. Drain the oil & leave it empty. Oil laying around in the sump won't do much good. Completely drain the gas and remove the filter. Remove the battery. Oil all bare metal parts. Cover intakes and exhausts as mentioned.
Before you get back order new plugs, oil filter, fuel filter, air filter and battery.
Tires are iffy. If you have the stands by all means use them, if not it may be more cost effective to get new tires.