The civilopedia is pretty good.
The differences between religions are just the differences that their temples give, the different units they allows, the different heroes they allow, the different techs/civics that they allow, different wonders they allow and then a handful of other things (Order gives a free unit when it spreads, FoL converts forests to ancient forests and triggers treants sometimes from ancient forests, etc.).
Is there anything specific you want to know?
Check out the online Manual by Xienwolf, it explains a bit better than the Civilopedia.
CoE doesn't show as your state religion to outsiders;
Fellowship of Leaves has no affect on Alignment; once adopted, it will quickly turn Forests into high-food Ancient Forests.
Strikethrough tag is [ s ] what you want striked out [ /s ] without the spaces inside the brackets.
I updated the manual to contain the information listed here as not being included.
If anyone feels like writing up strategy/introduction posts for the religions, it would of course be much appreciatedThough it'll be a while till the next release of the manual, lots of things to update and little time to do it.
Free units with Order is the last line on the page. 75% chance for a free Acolyte (or Crusader after Fanaticism) upon spreading the religion to a city. Not entirely certain that all of the other small effects are listed, but they really should be, as I just clipped some flavorful stuff from the forums, then placed a list of what the religion does. I had not listed the AC effects of AV religion nor the Ancient Forests growing for FoL.