The two councils are going to be reworked at some point. (The elohim can have access to the dark council as you say, they just need to switch their alignment first).
The bonus for the Unique features are intended to be minor, because they stack. Having three or four of those starts to be very interesting. As for the rest, in general, they're working better as a culture-victory civ, than a military-victory one, which is both lore-compliant and intended . (They will get a military-oriented leader at some point).
I don't think the exploration bonus makes much sense for them, but i'm open for discussion if you have any other idea ^^
Yes, I see them as a peacefuly and harmony focussed builder Civ that tries to keep the lore and prevent the world being destroyed. It ´s not easy to find and give them something unique as other Civs have already grabbed much of the cake, the exploration bonus is more for the austrin.
If they get something it should be something fitting to them and makes them special, hmm.
Here are some Ideas, I hope I get the exact english translation as I play in german language ;-):
Bard (Hunter) Spirit 1 magic spell (access to "Inspire" Spell) , 3 Movement , maybe bonus to defence and malus to meleeattack
Storyteller (Champion) Soul 2 magic spell (access to "Hope" Spell)
Phoenix or Griffon (national unit -4 limit, can fly)
Titan (national unit -4 limit)
Hero: Avatar of Sirona, Angel bound to the capital, can ´t move or attack, bonus to health regeneation, can cure illness poison
Buildings: Temple of Sirona
Race trait : Lore keeper + 10% Science of science buildings + 10% birthrate of important persons
edit: As Elohims are carebears and known for aiding ppl, explored tribes could give them a choice of reward, ofc no technologies but maybe (idea token from Civ5 -Civ Schoschonen)
- science boost
- gold
- unit
- random