Well, I’m not sure if I can help you but… if you want literally anything “possible,” I know there is a way to get the light-only part of the scene using one of the post processing nodes. But I’m not sure if you can use those if you aren’t making a post processing material.
You can try playing with it if you want though. 
It is one of the options for the SceneTexture node: Post Process Materials | Unreal Engine Documentation