By sound effects I mean things like the sound of cars zooming by on the F-zero stages, the lights turning on and off on Frigate Orpheon, etc. Can effects like these be added to custom stages?
(answered on smashboards. The short answer is "No"
http://smashboards.com/threads/is-there-a-way-to-add-sound-effects-to-stages.432038/#post-20943108)