Ghibli isn’t a character, but a style. You can’t copyright it.
Yes, the only test will eventually be "Can you train AI on copyrighted works"
I consider this article quite strong proof that generative AI is closer to copying than it is to creating a new derivative work.
For the downvotes:
https://www.copyright.gov/circs/circ01.pdf
“Copyright does not protect • Ideas, procedures, methods, systems, processes, concepts, principles, or discoveries”
Not sure why this is even controversial, this has been the case for a hundred years.