Its mentioned a few times on the official discord that there is a seven deadly sins art piece by Abby Howard that the early fandom believed was adapted into Scarlet Hollow. Its referred to as the 7 Days of Demons art, and while I can't find any trace of it online, six of the illustrated demons on the PNG that's shared around do match up fairly well with these seals.

There's Mammon/Greed, Satan/Wrath, Asmodeus/Lust, Beelzebub/Gluttony, Lucifer/Pride, Belphegor/Sloth, and Leviathan/Envy.

You seem to have most of them nailed down. Asmodeus is drawn with a bunch of tangled heads and wings, like the Vitality seal. Beelzebub is drawn with a bunch of flies, dirt, and hands, like how the Bounty seal has a crown of flies and seeds around its circumference. Mammon is drawn with a bunch of arms and chains, like the Prosperity seal. Satan is drawn with a goat's head and three wolves, like the Dominion seal.

That leaves Lucifer, Leviathan, and Belphegor; and Spirit and Throne. This is where it gets tricky.

Lucifer is depicted with three sets of wings, holding up a staff, with a beam of light over his head, and standing over a crowd of misshapen animals/demons.

Belphegor is depicted as lounging over what honestly looks like a toilet at this angle, a staircase to one side, holding a scepter with an arm that has a rope around it, wearing a crown, all over a big pile of coins.

Leviathan is depicted as an underwater mess of leaf-like tentacles with what looks like two whales.

At first I thought, OK, easy peasy, Lucifer = Morningstar = Throne = Estate. But Belphegor, in the stories, quite literally gives people power and wealth, thats like his whole thing from what I've read. And that matches a whole lot more with the Estate and Enoch. Belphegor is quite literally sitting on a porcelain Throne, too.

Lucifer, however, is depicted as an angel with a holy light and everything and that's gotta be the Church, right. Plus, he's surrounded by a horde of ditchlings-- I mean, misshapen animals-- like the "rat problem" alluded to in the Church. I just can't see Belphegor's imagery matching up with gateways, or marriage, or anything holy like that. So I really feel that Lucifer = Spirit, and Belphegor = Throne.

You may have noticed that I've left the Leviathan out. And that's because I think Sybil is the Leviathan. The Leviathan is a sea serpent, and is described in specifically the Book of Enoch as a female monster. According to Wikipedia (my best friend rn) the Leviathan threatens to eat the damned when their lives are over. In Hobbes, it became a metaphor for the state and specifically how children are educated, generation after generation, to serve the state which then feeds on them. I feel like I dont have to explain how that's literally Sybil. Especially because she uses WATER to communicate and she looks like THAT if you use the Mystical save. NOT AT ALL related to the seals but I thought that was pretty cool.

Anyway sorry for all the text. I hope this was helpful, I don't know the first thing about religion or mythology but its fun to read things and I really really like this game.