Light layout. Still no luck finding much reference for the actual lighting set up that Disney had. I will begin testing out the set up in maya.

Fog lighting tutorial: http://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU/Maya/files/mrfMS-Create-light-fog-using-mental-ray-for-Maya-sample-workflow-htm.html