this dungeon tileset seems to be over 4 years old, created by Daniel Thomas.
also 4 years ago AI generating was not a thing yet, so it is not AI.
EDIT: it is 9 years old according to unitystore.
I believe it is original assset that does not violate copyrights.
Maybe some ideas are from zelda, but this seems to be a legit asset.
https://danielthomasart.com/top-down-tilesets
https://www.fab.com/listings/8bd4d443-0e98-4b21-a634-fcee6295e39a
now for this snake temple, again maybe some ideas are from zelda, like this snake gate on zelda swamp palace:
it does look similar, but it is so far from the original that i think this asset pack is not violating copyrights.
and the original is 2d and the asset pack is 3d, so I believe this asset pack is ok to use.
this asset is also almost 7 years old, from time when AI generating was not a thing, so i think he did make this himself.
one of the byers on unitystore said 6 years ago that he likes the “Zelda-esque artwork”, so he also thinks it resembles zelda, but it is not originally from zelda.
EDIT: this one is 8 years old according to unitystore.
https://www.fab.com/listings/d23caf1b-9bcd-4d45-8277-4461e0191d59
so overall my opinion is that both asset packs are ok to use, and they do not violate copyrights.
as a sidenote: i find it very sad that i have to go to UnityStore to read reviews since FAB does not have a review\comment feature…