I'm into the idea of giving demon lords some cults and some distinctions. It's awesome.
These particular cults leave me a little meh, though.
IMO....
Baphomet is about blind animal fury, nature red in tooth and claw. It is bloody beast cults and the golden calf, the slaughter of herd animals, the bloodfeast and animal lust. Baphomet is nature wild and cruel, monstrous wilderness without control or limit, the beast that lurks at the heart of all of us. His rituals aren't hunts, they're transformations, the cultists are crazed predators and savage hunting lodges. Baffy's all about the unthinking primitive animal grunt, not the refined decadence. The labyrinth is a metaphor for madness, and a metaphor for the maze of life that traps all humans. Minotaurs can navigate this maze because they are beyond and above the walls, an animal unable to be caged.
Demogorgon is about internal struggle and madness. He's vastly intelligent and supremely adept, but riven, at war, and not whole. He is self-hatred, the feeling of self-interest competing with the feeling of self-loathing, the madness of a mind conflicted. He revels in breaking an individual, losing them to the depths of corruption and evil, unable to resolve this fundamental tension in their very existence in any way save utter madness. It's less alien cthulu weirdness and more hostile mental hospital cruelty, where genius and intelligence lie beside violence and cruelty. He's comprehensible and sympathetic because we all have an inner conflict -- he revels in exploiting it.
Grazz'zt is pretty good as a decadent creature of lust and witches, actually. Lets keep that.