What if SW8 is a Game of Thrones themed coaster, with trains styled as dragons & real fire and ice elements throughout the ride (possibly the large person-like structure is indeed on fire in some way?). Perhaps the launch element is part of a ride narrative about escaping the army of the dead?
Alton Towers could even be working with their old friends at Tussauds to create waxworks of some of the main characters, which would feature in various themed rooms that you pass through in the queue section. The March 2018 opening would of course tie in with the final season arriving in the summer and would be a massive PR fest for the park.
If this were true then AT could be going with the Wicker Man-esque theming as an elaborate ruse to keep the project a secret, as anything remotely GoT-related would be instantly recognisable...
I could have just dreamt all of this up with zero evidence, of course