Might be best to heavily rewrite the page to save everyone the legal headache

Are you basically saying that somehow Tv Tropes owns the content inspite of the fact they'll never even be bothered to use it at all?

That's utter bullshit.

Does that also apply to All The Tropes site as well?

Yeah, that's how their license works. But even if it was still on their old one, it kind of leaves you on shaky ground to copy & paste the entire page like that

I remember that new owners of Tv Tropes bought the licensing issues with real lawyers, found about how much legal hotwater they could get into, and they scaled back on that a bit but still a bit murky on what we can use.

About All the Tropes, it has the same license as this wiki, so copying and pasting from there seems kosher. So does the wiki's here on fandom dedicated to shows, movies, anime, etc.

Note: copying, pasting, AND crediting.

Yeah, I forgot about the REF tags. At least, you don't read like "Gaiz, this is for real" or "My dad works at Nintendo.

You're talking about the reference system, which mainly is used for sourcing. Crediting means "I got this piece of content from X", Sourcing means "this is the place where I found this quote or support for this statement". Similar but largely distinct.

Crediting in wiki terms is usually done using the history system or including a boilerplate text somewhere like "this section/page is based on/copied from page Y on wikipedia/other wiki".

Well, you can add the history of a page to another. I've known about that for quite a while. However, there's a little problem with that, at least for me, I never really understood WTF is "interwiki prefix"?

Probably not because you can only add your own edits to this site.