Old post I know, but if I had to put Sanguine, Vaermina and Malacath anywhere, it'd be fiend, aberration and celestial respectively and here's why

Sanguine: While it is true, his brand of sin is mostly just becoming the worlds biggest partier, temptation is still temptation, and hedonism can still lead to ruin (addiction, broken marriages, etc.)

Vaermina: You said it yourself, her domain is over the mind, or more specifically dreams. Aberrations more often than not (IIRC at least) cause psychic damage which I imagine Vaermina's brand of nightmares would cause.

Malacath: So we gotta dig a bit deeper for this one. Malacath is stated to be the corrupted form of an old Aedric being known as Trinimac. Trinimac was deceived by Boethiah, who tortured and corrupted him into becoming Malacath.