Steve Bannon was the chief architect of Trump's scorched earth campaign strategy. He didn't invent Trump's viciousness but he certainly honed it, and he is more responsible that anybody for the cancer of lies that won Trump the presidency and continues to guide this administration. 

Extolling whatever modicum of religious virtue he might possess has a "Hitler loved his dog" feel to it. In the end, it really doesn't matter. This man is largely responsible for the destructive state of polarization in the body politic, and that will be his primacy legacy.

Besides, anybody who thinks Bannon's Catholicism had some kind of tempering influence on Trump is fooling themselves. When it comes to religion, Trump is influenced only by those Evangelicals who flatter his ego and excuse his excesses.