I don't understand why people think religious people will go bananas if aliens are confirmed. There will be unrest at the beginning, sure, and probably more than one dangerous alien based cult will rise. But most of the religious leaders will just adjust their narratives and try to retain as many followers as possible. And most followers will be eager to take explanations and not challenge their core beliefs. If I remember correctly, the Catholic church said they are not opposed to the idea of intelligent life and civilizations outside earth, so it seems like they are somehow prepared.

I think most religious leaders are smart enough not to rush to the "aliens are demons" conclusion, specially if they are proven not to be hostile (I assume they are not if the government are dealing with them).

Why stop at religious people? Most people probably wouldn't be able to go back to their lives after discovering there's a whole new dimension of things out there and there's a possibility to travel and see very weird things.

So far we've sort of come to terms that we're alone in the universe and the great void is unexplorable. But what if it isn't? Wouldn't everyone just want to go out and do some Firefly-grade shit? How would one just go back to performing risk assessments for insurance companies after learning that?

Hmmm, I'd argue the idea of God is anything but 'terrestrial', maybe even bordering on 'extra-terrestrial'?