None of these religious arguments seem relevant to me. The Bible does not mention dinosaurs, yet their existence has not thrown the religious into a tailspin. Bacteria exist on earth, so their existence elsewhere isn't particularly troubling. If God created "the heavens and the earth," and placed everything where it is, I don't really see a crisis of faith in thinking that God put something on Mars while he was busy creating it. Those that believe the Bible/religion is a guide for morality and spiritual beliefs rather than a literal account of actual events will have no problem with this at all, as it's simply discovering the vastness of what God created. Those that believe the Bible is a factual telling of history already believe crazy theories about dinosaurs and are willing to say that anything is possible when you have an omnipotent being - how could literally anything sway those people? What possible argument is there against, "God can do anything"?
Go ahead and tell me that, if you were omnipotent, you wouldn't try riding a T-Rex while carrying an automatic weapon.
Yeah I'm sure the YEC's here in the south will totally start believing in facts and logic if this turns out to be true. When you've built a large part of your life based on myths and fairy tales you aren't likely to change your views.
For a lot of people, I think this will be exactly the case. And it seems like a logical argument to me, even though I am atheist. For friends and family who do believe in the bible, this is how I would suggest they look at it if/when we discover life on mars. The issue comes up with other religions. For example, how do you think the militant spin-offs of Islam are going to take it? (I'd argue that militant Islam, like that practiced by ISIS and the like, isn't Islam by nature, but that's for another thread...) As far as the implications of life on Mars, I think that it's going to re-define what we view as "life." Here's what NASA has to say about the definition of "life," but I think what we find on Mars -- or elsewhere in the solar system for that matter -- could well be something entirely new.