Cassius, thank you for starting this thread, and glad folks are finding the essay of interest! I became intrigued by Gassendi for reasons that have been touched on in the thread--i.e., he's a crucial link to the modern era. I was specifically interested in his take on "liberty" and how this links up with the modern understanding of the term. And then I noticed that "Happiness" had relevance to some of the things we have been discussing in the forum and our Sunday sessions.
Certainly some problem areas, as both you and Patrikios (and Karl Marx) have pointed out. So I'm also quite interested in the divergences, some of which you have identified already. Regarding Gassendi's dismissal of active pleasures, I see that he is going to great lengths to distinguish Epicurus from Aristippus, and maybe this leads him to overcompensate by implying that Epicureans were sort of proto-monastics.
I've only started exploring his work and don't have a good read yet on the availability of translation. I started with the 1699 text, then had a look at the PDF I shared and decided that it was reliable. It's certainly easier to read! But I'll continue poking around.
Patrikios, you've really got me interested now in Marx's take on Epicurus. The fact that Epicurus influenced thinkers as divergent as Jefferson and Marx blows my mind.