SceneWorld vs. Scene?

Resorting back to forums because I can't seem to get an answer anywhere else:

What is SceneWorld/SceneObject vs. Scene/GameObject? - What are/was the intended purposes for SceneWorld/SceneObject? If they are being depreciated, how are they going to be replaced?

I'm currently using a custom Skybox due to hardcoded file names - it relies on a SceneCubeMap which derives from a SceneLight which is a type of SceneObject - how am I supposed to be using these, if at all? What alternatives should I be using in place of any SceneX related classes?

I can't find any documentation outlining the differences or use cases between the two so I am cautious as to what I should be using and where. We were told SceneWorld/SceneObject is going to no longer be used in future - so how is that all going to be handled? Even things like lights all rely on SceneLight at some point in their inheritance - are they all changing in future or are SceneObjects etc. just going to be locked away from general development?

I want to make an educated-as-possible decision on how I'm going to handle making what I am, but when I look through engine code for examples to build off of there appears (to me anyway) a significant amount of classes and engine functionality that rely on these things.

Okay, so for example a cubemap - there is SceneCubemap which is internal and EnvmapProbe which is what we should be using/inheriting from? 

In my case, am I safe to make a custom Skybox using a SceneSkybox, given that Skybox2D is where my issues are?

Thanks, I'll try and make do with what is available as GameObject/Components and make issues if I find I need more functionality.