Temporal Rune of Leaves can be obtained via alchemy or from the Cave of Wonder starting from level 3.
Temporal Rune of Embers can be obtained via alchemy or from the Cave of Wonder starting from level 5.
Lava Inferno and Meteor Storm can be obtained via alchemy.
Molten Core does not have a level unlock requirement in the alchemy page. It does however, require Lava Inferno in its recipe. To alchemize Lava Inferno, a player must be at least level 175. So technically, Molten Core also requires a player to be at least 175 to be able to obtain it.
Mystical Scroll of Atlantis and Elder Scroll of Atlantis can be obtained from the Atlantis II's Underwater quest.
Must be at least level 100 to perform alchemy.
Helm of the Deep is also a Divine Item.
Since Helm of the Deep requires 2 Krakenhide Armors in its recipe, you will actually need 4 Brilliant Scrolls of Atlantis, 17 Mystical Scrolls of Atlantis and 6 Elder Scrolls of Atlantis. More if you want to create a third Krakenhide Armor to keep. Good luck.