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"

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.