There are innumerable "feelings" and emotions within those two categories, but every sensation is either pleasurable or painful. That seems to be a very insightful discovery, and seems to be born out by current psychological affective research... but we're not going down that road
This statement helps clarify the difference in perspective, because i do not see this as a "discovery" at all -- it's not like he "observed" or "put his finger on" some previously overlooked characteristic that is inherent in certain activities that makes them agreeable. He "decided" or "defined" all agreeable things (as determined by mental and bodily feelings / reactions at any moment) would be called "pleasure" (or hedone or voluptas or whatever language) and all disagreeable ones would be called "pain."
Epicurus could have chosen any number of words / divisions that he liked ( e.g. he could have called some "noble pleasures" or "worthy pleasures") and so established some kind of arbitrary hierarchy within the term "pleasure." But he instead said (decided / defined) "I need one word to describe all that I feel to be agreeable" and I shall call it "pleasure." i would say that is a "philosophical choice" which makes for a "worldview" rather than a "discovery." Many other people - Cicero and essentially all philosophers besides Epicurus - choose to assign the labeling differently. Rather than calling the standard non-stimulated condition of life by the term "pleasure," they assess that standard condition differently, and they call it "neutral" or some other in-between word suggesting a less positive assessment.
Finally, I don't think Epicurus is necessarily redefining "virtue". It seems to me that "virtue" to Epicurus still means generally "to do what society feels is the excellent/noble thing to do" but for Epicurus we do it because it brings us pleasure, both as the feeling and leading to a more pleasurable life (i.e., PD05) Virtue has no intrinsic value *other than* to serve as an instrument leading to pleasure. And now pleasure is widely defined!
Now that one I doubt we'll be able to bridge very easily, because I cannot see Epicurus holding a "virtue" (such as wisdom) to be "what society feels is the excellent/noble thing to do." I would think that Epicurus would have deferred to "society" in defining the attributes of "virtue" exactly as much as he deferred to "society" in defining the attributes of a "god."
But yes regardless of where we end up this discussion is extremely helpful toward bringing clarity to the questions!