I don't like the Grigori as early rushers or warmongers. I'm also not a fan of your proposals. They don't make a whole lot of sense, and they seems extremely hard to implement.
A couple things I've proposed often before:
Make Luonnatar appear earlier, and with more abilities. I like making them require Philosophy, but also moving Philosophy to come 1 tier later (requiring either way of the wicked or way fo the wise, and not being a prereq for Priesthood), be more expensive, and be the prereq for Republic. I make Luonnatar weaker, but let them target disciples in stacks. I remove their channeling and Inquisitor promotions, but give them a unit-specific spell, "Enlighten," which works like Inquisition but ignores state religion, letting them remove even the state religion from neighboring cities. I also let them move though rival territory without open borders, so that they can do that more effectively. I'm also thinking it would be nice for the spell to be able to remove religions from units. Disciples that give up their religion might have a chance to defect and become Luonnatar, or they might just loose their faith and so not be able to use spells anymore.
I like letting upgraded Adventurers have a spell that turns them back to Adventurers, with all their promotions and levels intact. Immortals that have experience as Beastmasters and Archmages are awesome. Of course, this doesn't exactly make them more pacifistic. It might be a good idea for Adventurers to loose the Hero promotion (especially since the Natherblade, which give the bonus vs Heroes, is said to "strike strongest against those whom the angels have favored most;" I don't think that anti-religious Grigori are the Angel's favorites), and get a different "adventurer promotion" that grants the spell, better results from exploring lairs, and extra xp from combat. Also, some units would need changing to prevent exploits (like adventurers being able to get an infinate number of free promotions if they keep turning to arcane units).
I also usually let Adventurers settle as "local legends," which generate culture, adventurer GPP, and 1 xp for units built there.