yeah it's going to be an interesting next couple of years for sure.
If you clean room reverse it, the mechanics in a Legend of Zelda game are, for the most part I think in the clear legally speaking. But part of what makes Zelda feel like Zelda (IMHO) is that you’re fighting familiar monsters in a familiar setting with familiar music aka all the lore, otherwise its you've just rebuilt an open world exploration game with dungeons.
However if you borrow lore like even if you change the names of all the monsters, you may still run into legal risk if they remain visibly recognizable. Even if you redraw them in a different style, if they’re still identifiable as Octoroks/Moblins/etc, that might still open you up to litigation.
There was a similar case a while ago, Tetris v. Xio, which might be worth looking into, since I think it sets some useful precedent.
https://en.wikipedia.org/wiki/Tetris_Holding,_LLC_v._Xio_Int....