Just read your edit Ben,
by AFX I assume you mean after effects in which case the rain was added by our compositor with fusion using some stock footage. Also added some lightning in a couple of the shots to try and make things look more epic. Will try to go into more detail about the methods he used once I get the animation up as it will not make much sense without seeing it. Have started to realize though how imperative compositing packages such as after effects and fusion are though if you want to create great work. Also the main passes that we use are z depth pass, shadow pass, object normal pass, beauty pass and then often render out objects in solid color so they can be manipulated easily.

As said I will try to go into more detail on this when I get the final renders.