personally, I do not see much if any correlation between attic ventillation and paint peeling on the exterior siding. But, I have seen paint peel on the adjacent exterior wall of a bathroom that was leaking moisture in the form of condensation due to hot showers and hot steam.
First, you may have two issues going on. If you would improve the ventillation or change of air in the attic it will assist your heating/cooling considerably in the livable units. You need to unclog those soffet vents or probably cheaper is to add thermostat automatically power roof vents. This would get the air moving and changing out.
Most likely the paint is peeling due to: improper prep during the last paint job and cheap paint or paint NOT procured from a paint store, or just natural aging. In my opinion, a good paint job will need re painting about every 7 years. But if done properly the first time, the re paint in 7 years would normally only be light prep and re paint. Chipping and peeling would not be the case.