Render layers and setting up render passes: one to one with Sang Yu

I've had another one to one tutorial session with Sang Yu, to make double check what render passes are required.
In order to make sure my scene is glitch free I am creating a base scene file, which will include IBL (Image Based Lighting), a section of tree, four ice men and an image plane.
To set the scene, and make sure the scale and eyelines are correct, I will use an image plane with a screen shot of the live action footage of the lead female character (Kerry Flemming actress) below.

Once the scene is set I can then remove the green screen shot from the image plane and replace it with a sequence of tiff files, showing the timelapse footage of the moving clouds
This timelapse footage will not form part of the final render, but is used so that the refraction of the light will be seen purely in the icemen...
The aim will be to comp all the green screen woman, the CG elements and the actual moving clouds timelapse footage together in Nuke; and for the refraction of the moving sunlight to be captured within the animation of the ice figures

Here's a recording of the one to one tutorial that I had with Sang Yu, to establish and set up which render passes will be required

And my previous one to one with Sang Yu, to establish the render settings, particularly with refraction.

Test render to tree section, with new bark texture