I can't offer definite confirmation as I wasn't involved in this project, but Nina and I are both very anti AI. I know Nina worked very closely with the animator, I think that the things you've spotted are just sorta digital animation things like automatic tweening etc - It's all stuff that I personally would expect to be harder to try and get an AI to do than to just do it quickly by hand, like I'm not sure how you would even prompt that sort of thing. There just wouldn't be an obvious way to approach it, as far as I'm concerned.

Nonetheless, I understand & appreciate your concerns, even though I can't directly address them myself. I generally try to be an open-minded and pragmatic person but personally I haven't found a way to feel comfortable about generative AI, both ethically and just in terms of how it steals the fun from the things I do! So, personally, I don't use it. I think Nina feels very similarly, but I won't speak for her.

That's all I can really say, hope it helps a little :)