Elh No.
They and the Hist are two separate Dawn-Era creatures.
The Hist were also bystanders in the Ehlnofey war, and most of their realm was destroyed in the crossfire.
The Hist have a different beginning.
They are - in simple terms - Trees, and have always been such. They have a network of roots that link them, and they are spiritually tied to the Argonian people.
The Hist Realm was destroyed by the Ehlnofey despite their neutrality. Part of it became Black Marsh, most of it sunk in to the sea, some became a part of Clavicus Vile's realm, and a small part remained as it's own Oblivion plane.
They are neither Aedra nor Daedra.
Just throwing this out there as an FYI, but the Sleeping Tree in Skyrim (game) is believed to be a Hist. Its origin is a mystery, but it likely fell from the Floating City. This could explain its look, because there's a novel about the city, and an Argonian mentions feeling the pull of a Hist, when near these twisted looking trees.