I've heard of non-literal interpretations of Revelations. Fine. But I've never heard of the 666 in any positive way. I've never heard of God being the source of the 666. The Beast uses it. So, of course if you consider audience then you might lose some people. Considering how fractured the modern church is then you might not lose a ton of readers. I realize that your story is not a biblical critique but some of your audience might not like it. I know that there are things you won't fool around with (e.g. birth, death, and resurrection of Jesus), many people would not like that, but I don't know people's limits on the 666.
I learned about audience considerations on this website so let me apply it! :-)