I can't believe even the staunchest ancient Epicurean really thought that **everything** Epicurus said was blindingly unique. We all know much of what Epicurus taught he learned from starts others had made, such as Democritus. So it's only natural that smart people do regularly hit on similar thoughts. The uniqueness of Epicurus comes through in certain particular ways, and it's probably most helpful for us to think about those particular ways and the reasons for them. That's the obvious way to sniff out when someone who's talking - for example - about "virtue" is speaking as an Epicurean or Stoic or whatever.
It does seem that having a basic knowledge of all the ancient philosophies could be helpful.
Perhaps...the uniqueness of Epicurus is deconstructing and replacing the "perfect" and the "ideal" and properly placing pleasure (together with the removal of pain) as the best guide to a good life. If you think about it, it is only the wealthy who can try to buy perfection (or vain opinions) in the lifestyle that they pursue. (And then sometimes others who erroneously envy the wealthy). But the necessary pleasures required by nature are easy to procure.
He references the similarity to VS54:
54. Do not pretend to love and practice wisdom, but love and practice wisdom in reality; for we need not the appearance of health but true health.
There is also the reference to health in the Letter to Menoeceus, in the opening:
"Let no one put off the love and practice of wisdom when young, nor grow tired of it when old. For it is never too early or too late for the health of the soul."