Motor oil, would not worry about leaving it until spring unless it has been run for hundreds of hours on that oil. Gear lube , now. If there is water in the oil it will crack your gear housing over winter.
The theory is not leaving old oil in the engine during layup. The outdrive is more important to change because if there is a leak, you don't want a mix of oil and water in the outdrive over the winter and freezing temperatures. Our old Correct Craft never got the oil changed in the fall, always in the spring - never an issue in the 2000hrs we put on the original engine.
For me, I change all the fluids in the fall - I already have things out do to the outdrive, so I just do the oil and everything is ready to go in the spring.
I actually brought that up a few weeks ago in a thread because I got hurt mid and July and only put about 5 hours on new motor oil and new drive oil and was told I can just leave it because it has so little time on it