That was a deep dive ... I look to Max Weber's book on Protestantism and the Rise of Capitalism. He cut and pasted in a large section (perhaps all) of Benjamin Franklin's "The Way to Wealth." Personal virtues of thrift and hard work were evidence of your personal salvation. Franklin enjoyed himself, as we know, but he made his money in the city. On the other hand, despite all of his intellectual achievements, Thomas Jefferson was a land-owning, slaveholder, and a perpetual debtor who borrowed money to indulge his passion for books. So, those two paradigms exemplify different lifestyles, depsite both men being "Protestants."
I see, also, in the mass conversion theory a lot cultural Objectivism: if we can get enough people to read Atlas Shrugged (or see the movies), we can change the world, bringing about a "Rebirth of Reason." I certainly am in favor of the outcome. It is, however, an individual enterprise with a personal reward, whether or not the rest of the world changes.
Catholicism is like any ism... it depends on the person living it. Before he was tossed in the cellar here, Ted Keer recommended the works of Cardinal Mercier (See Wikipedia for Desire-Joseph Mercier.). I got his textbook on philosophy from my university library. Except for the expected passages about God and Christ and Salvation, it could have come from an Rand's own inner circle: the senses are valid; and reason informs us of what we perceive; and all the rest. Even the ethics were mildy - not wildly - altruistic, noting the benefit to the individual in acting morally (granted that the morals were fundamentally in error). It was why Rand nodded to Aquinas.
But, it remains that there are Opus Dei Catholics like Mel Gibson who share many "Protestant" ideas about salvation and works here on Earth. I was fired from a job with Blue Cross of Michigan when, at lunch, my project manager asked me if I go to church. I said that I don't discuss religion at work because you end up arguing whether the bishop of Rome is the vicar of Christ. At that point, the other person on our small team spoke up to witness for Jesus. The manager chimed in that he, too, knew Christ as his Savior because of his Catholic religion, even though other Catholics are caught up in ceremony and ritual. And I had nothing to say...
But I just note here and now that the broad generalizations and angels-on-a-pinhead analysis of Peter Burfeind are somewhat peculiar. He is, as he notes, worried about the continued spread of Gnosticism.