The color of the shingle is more important than venting or non-venting. And temperature is less important than the shingle getting a sunburn. The biggest impact on shingle durability is ultra-violet light. UV is more critical than temperature. The best roof for hot, humid climates is a concrete or clay tile roof.
Crawl spaces are real simple to understand and deal with.
When you vent crawl spaces you bring in hot, humid air and cause moisture and mold problems. The ground surface is typically colder than the dew point temperature of the exterior air. The underside of crawl space floor insulation is radiation coupled to the ground surface and is very close to the same temperature of the ground. Moisture droplets can be seen all over the top surface of typical polyethylene ground covers as well as hanging from the bottom surface of the crawl space floor insulation. It must have leaked through the walls.