The Star Wars At A Glance posts are particularly intriguing/illuminating here (specifically the end of the Y-Wing post, the B-Wing post, and “Unsung Heroes of the Battle of Endor”). You have to wonder if the elimination of Vivienne Chandler from the film is a result of Black Friday (and not having enough time to re-do all the effects for her role), or maybe her performance wasn’t that good (see also: Dermot Crowley’s reduced role as Crix Madine), or if the Battle was just way too long and bloated. Unfortunately, it’s probably impossible to discern the truth as it may be a mixture of the effects & bloat (like why they cut Jerjerrod’s moral dilemma).