There is an Area of Effect "Cube" that does occur at the point of impact. The cube can deal module damage to the things inside it (engines, aa mounts, rudder, magazines, etc...) but does not start Fires.
This is not correct. The AoE is not related to the Fire effect, otherwise you could light a ship on fire when HE shells or bombs splash in the water nearby. Fires can only start after a hit from an HE Rocket, HE Shell, or HE Bomb.