As Seymour have Norman and Murray still, and are currently painting them blue, I'd assume they are running it, and appear to be planning to use S303 and possibly B74 at the noisy end, as both are or will be repainted. Add to that the numerous S cars they have, and IIRC they have CS1 as well, and they've basically got the consist covered. Surprising they do not mention the tour anywhere though.
Totally a wild stab in the dark, Steamrail *could* be planning to run a seperate train labelled as the Spirit, but as I said, I could be way off.
Norman was sighted being in Blue on Saturday, she was all masked up to get the yellow lines.
Check out http://www.steamrail.com.au for more information regarding the Spirit Trip on the 17th of November. Details will be at hand shortly. There is an advert for the trip on the main page of the Steamrail Website.