Air doesn't get into the lines from vibration. It gets into the lines via a leak.
You should be fine.
Air doesn't get 'into' anything. There's a certain amount of air inherent to any aio, which is perfectly acceptable as air compresses and coolant does not, so changes in pressure, either atmospheric or thermal, doesn't stress fittings or components.
Coolant is made up of chemicals, all made up from molecules. Temp changes, pressure changes, mechanical abuse and time will cause degradation of the coolant, which breaks down over time into it's molecular components. This puts free molecules into the loop, some of which are smaller than the molecular makup of the hoses.
Oxygen is by itself a small molecule and permeates over time through the hose, even though they are low-evap hoses. Nitrogen is a far larger molecule than oxygen, so gets trapped inside, either forming a gas or recombining with other molecules, so over the space of 6 years or so there's not just a lower amount of coolant, and more gas, but the coolant itself has lost its purity and started becoming something less efficient.
Think about a boiling pan of dirty water. It's dirty, but still water. Boil it down, steam all gone, fluid level gone and nothing but a pan full of mud at the bottom. Same principal.
Will the sub's vibrations affect the aio? Yep, sure will. Instead of getting 6years out of the aio, the additional vibrations on the coolant over and above any vibrations already present from the pump could easily drop that to 5years and 11 months. Having an affect does not always mean it's a meaningful affect, or a large affect, either negative or positive.