Well, looking back through the 6th Astral Era log on the character info bit on the site, I did indeed complete that part of the quest line.

"Takane Shijou has completed the Immortal Flames quest "United We Stand (Ul'dah)"!

And also:

"Takane Shijou has acted jointly with members of other Grand Companies to destroy the lunar transmitter inside Castrum Novum!"

Still didn't see the alternate opening. Not really that big of a deal, just wondering if there's more prerequisites to seeing it than just that. I did move servers and change my character a bit from 1.0, but not sure if that'd have an effect on it.