OK I am at a stopping point for the moment but I want to conclude by agreeing with this paragraph from Jackson in most respects, except for the implication of the part underlined in red. I don't think the Epicureans thought that the the gods were real because it was important to think of them that way, I think the Epicureans thought the gods were real, and that it is important to think of them as real, because of the various arguments that they made in favor both of their existence and of the function that contemplating them serves for us.
With the caveat that the word "religion" is so polluted by connotations as to be almost useless, I do also agree with the observations that the Epicureans saw their philosophy not as anti-religion but as a purification of religion, purged of its absurdities.