Hmmm... how to go about this.
Okay, there's things that are blasphemous but not really offensive to most people. Saying "God, what a crappy car" is blasphemous, but no one is really going to take offense to that, except super Christians.
What this is though, is a direct mockery of the religion and the people within it. It doesn't matter that you are Christian and would not take offense at it, because the act in itself is EXTREMELY offensive, even if you call it parody. As sysadmin said, let's take it to a place and make it not religion.
Why don't you re-enact Roots, in blackface and all, but make it anime. And instead of KuntaKenta, it would be Mr.Popo from DragonBall? Do you think black people won't find that offensive?
Or let's re-enact Nanking, and instead of China... it would be Anime... like a hentai movie. Totally not offensive right?
You're specifically taking a major part of peoples' lives and culture, and turning it into a huge joke. You're mocking their style of living, and their beliefs and making out what they believe in to be nothing more than trivial and insignificant.
I personally hate religion. I think the idea of religion is stupid and pointless, but I respect other people enough to allow them to have their religion and believe in it. What you're doing is basically the exact opposite of what the protesters are doing. They're trying to promote and force religion down other peoples' throats. You're mocking them, and telling them their religion is stupid and trivial.
Would I be offended by this? Absolutely not, but even I recognize how incredibly offensive this is to other people. Now...
Let's say Fanime has this. Let's say you somehow convince Fanime into doing this. How is it going to look on Fanime's part when religious people that attend fanime, or religious parents thinking about letting their kids go to Fanime, see this in Fanime's line up? Do you think these parents are just going to go "Oh, this convention is mocking my beliefs, but that's fine, you can go kids."
I don't see how you can possibly see this as not offensive?