Phaedrus was a Scholarch of the Garden, a successor in a long line of leaders of the school of Epicurus. Philodemus was also a devoted member of the school, having studied under the Scholarch Zeno of Sidon.
Lucretius is probably the outlier here--a Roman among Greeks, as it were. He held orthodox beliefs about the gods, and was not an atheist, but he was more critical of cultural religious devotions than Epicurus was.
Excellent summary, Joshua !!
There's a whole thread on On Piety:
Thread
Philodemus On Piety
Check out what came in on interlibrary loan this afternoon! I'll share thoughts etc on this thread. Stay tuned... epicureanfriends.com/wcf/attachment/1550/
Don
In addition to it having been referenced elsewhere on a number of occasions.