There isn't any overt Christianity in the Perelandra stories, but C.S. Lewis' basic morality comes through, and the planetary spirits seem angelic in nature.
Jim Butcher is quoting C.S. Lewis through the voice of the Archangel Uriel when he says to Harry, "You are a soul; you have a body."
I'd be hesitant on ascribing anything in regards to morality to Jim's quote there. Sounds to me more like the character's using it to explain that in the Dresdenverse, the soul is what makes up your identity, self, etc, while the body is just the earthly walking around suit it drives until going elsewhere.
Which naturally leads us to speculation on exactly how things work with the beings that don't have souls, if sentience isn't the hallmarks of soul ownership in the Dresdenverse, what is? Kind of reminds me of the buffyverse, where when a vamp takes someone, the soul goes away, leaving a demon-run shell that still has that person's memories, but is in no way actually that same person. I'm guessing the Red Court works that way.