I say we go for prophets, Divine Cult looks a little iffy to me. That extra unhappiness just screams rioting.
We need to get to writing ASAP so we don't have to war with everyone everywhere, but it's so far away right now....
What extra unhappiness? The one from non-state religions that won't even spead into our empire? The one we can build inquisitors to remove?
Hang on, I'm gonna start up the game again to make a list of techs for comparison.
EDIT: Alright, here's the civic comparison:
To be honest, Divine Cult is the best option here. Naghualism is basically tailored towards slavery and divine cult.
As for the techs?
Most of the prehistoric techs are self-explanatory - Elephant Domestication gives us elephant units, for example. Falconry gives us Trackers, who are improved Hunters. Megafauna Domestication gives us Bear Riders, amongst other things. Boat Fishing reveals pearls and sailing enables lighthouses, galleys and beacons.
Ideograms, Board Games and Oratory are prerequisite techs.
Agriculture lets us build farms, Archery lets us build archers, Caste System enables the Caste society civic, Folk Dance and Folk Music increase culture, Naval Warfare enables War Galleys, Fungiculture enables various mushroom-related buildings, Orchards reveals olives and lets us build orchards, Pottery enables granaries and potters and lets us build cottages, Apiculture enables apiaries, Priesthood lets us build temples, The Wheel gives us better roads, Candle Making speeds up workers, Mining reveals various gemstones and lets us build mines, Fermentation lets us build a bunch of buildings, Ancestor Worship increases culture a bit, Dualism would normally found Zoroastrianism, and Divination enables Prophets and the Oracle.