Do you _actually_ think developers actually finalize all animation content before anyone is allowed to see the game? What do the animators do for the rest of production, play foosball?
Animations are designed, prioritized, scheduled, created, reviewed, revamped, re-reviewed, and tweaked like any other art asset. Placeholders and rough animations are perfectly normal during early stages of development. It's not like the words "new animation" have never been seen in beta patch notes. If late in beta a designer decides that a particular ability activates way to slow and they need to cut the time in half, and thus need a totally different animation, do you think production just tells them too bad, or do you think they adjust the animators' schedules to get a new animation made, potentially deprioritizing of some emote no one cares about and that wasn't scheduled to land until launch anyway?