With regards to BATB, I think the solution may have arrived from Disney, no less.
The work-in-progress version on the BD, from what I could see, is definitely film sourced, and appears very dark indeed.
It is not branched with the special edition, but is on a different file.
I'll be sending a rip to Andrea so that he could compromise on the brightness settings for his project, as the brightness setting on this print is meant for the cinemas and not for home viewing.