The cinematic doesn’t play in game during the quests that introduce the Darkshore Warfront. You might be thinking of Tyrande’s Night Warrior transformation, which did play during the scenario in those quests.
And you’re right, an updated version of the datamined cinematic was found in December, which had music added, but Genn and Mia are still in it:
As far as the quest “A New Hope”, it is technically in game, oddly enough, just hasn’t been made accessible. However, if you have a Nightwreathed Watcher collected in your pet battle journal it will tell you there are three sources for it: Grimhorn for the Horde, Orwell Stevenson for the Alliance, and the quest “A New Hope”, though this could just be leftover data in the game that they missed removing.
Though, as far as things that were scrapped, because there’s only one general leading the Darkshore Warfront instead of several, I did a write up on analyzing the timeline based on what we have in game here: