I wonder if the web.archive site has any permissions from Inno to use their images and other proprietary documentations. For that matter, I wonder if the owners of the original Gems site approve of their site being hijacked even if they let their website expire. Just a thought.
Copyright laws have exemptions for archives and libraries, and Wayback Machine is part of Internet Archive. The material isn’t being sold or used in anyway but only archival purposes. They consider themselves a library, but I think there was controversy a few years ago at start of shutdown bc they opened their archive for “borrowing” (they also have books and movies) like a regular library and some content owners were not happy. Even a brick and mortar library need to pay for books and digital material like audiobooks before loaning them out to public. In the past I have talked to a librarian who said with digital material, the library pays by the downloads. It’s not like paying for the audiobook once and renting it out in perpetuity for free and incurring only server costs afterwards. They have to pay for it again after x number of borrows. I don’t think Internet Archive follows those rules.
As for Gems, I would think they fall under fair use. They are using the material in a transformative way to comment, review, and educate. They are serving ads though so one might argue they are making money off the content, which would muddle things a bit, but it does sound like they straight up asked Inno to be clear. Either way, fair use would just need to run its way through the courts and up to judge to decide on case by case basis. Most will probably cease and desist you first.
(And Shenanigan Elves fall under Fair Use parody.)