Well, I can't believe I was so stupid -- there's even cards with pictures of the Emperor hanging upside down in the book -- but I realized last night that the major characters might all match the Tarot Major Arcana. I printed a list of all the Tarot face cards and today I went to the library and pulled the book. I skimmed through it and indeed, the characters are based on Tarot. That doesn't actually make the book any better for me, but I emailed the others about it.
I wonder if Scott Card would have pushed Tor to publish it and then written an enthusiastic introduction if he knew it had to do with pagan stuff.