Yes, vent anything and everything.
It is an enclosed small space mostly made of metal and wood.
Temp differences and moisture has to be controlled for long term benefit.
I have asked the same question and seen the different methods.
Ideally, a vent system capable of exchanging all of the air in and out of your skoolie is best. A Fan-Tastic-Fan works well, dual direction in and out, varying speed all that. Some of the higher grade models can exchange more cubic feet of air than your bus can contain within minutes.
One bus that I have toured locally, had both a humidifier and dehumidifier for seasonal use given our location and extreme climate swings.
Both have to be monitored and balanced, you will find rust elsewhere before the paint above your cook area is impacted. A rusty bus is a nightmare speaking from experience plus, uncontrolled moisture sparks life in the form of mold. High moisture and low air exchange will destroy your health and bus in time. I know it sounds like a lot and difficult but, it is not. It is all trial and error, you will find the balance and be fine. Keep researching and planning, the more you research now the less - what the hell do I do now - you will have in the future.
D.L. Jones III