However, George MacDonald and Frank L Baum and J.R.R. Tolkien and C.S. Lewis wrote stories about protagonists who go on a fantastical Journey to learn not to show off what they already know. And so Narnia works as a Christian story the way it does because the Pennevises are not very Biblically or Theologically Literate, Narnia has to teach these children what modern education neglects.
And yet I as a Christian who has a lot of theological and doctrinal disagreements with Tolkien and Lewis even though I’m a fan of their fiction, feel like the Modern Anime Isekai approach is actually a better framework for Christian Fiction because you can frame it as a missionary journey, a quartet of modern Christian Nerds like myself sent to like Paul and Barnabas bring The Gospel to people that hadn’t heard it yet.
I’m also more Politically and Socially Leftist then either Tolkien or Lewis and that'd be reflected in anything I wrote as well. They are sent to preach the Gospel to those willing to hear it but NOT to impose anything, as believers in Universal Salvation they won’t go around telling anyone they’re going to Burn Forever if they don't accept their message. If they do wind up influencing any Governments it’ll be in a Communist direction. Instead of siblings the four will be Polyamorous Pansexual Lovers.
I’d also take the approach of a world that has had migrants from our world in the past, in fact I'd trace all Sapient life back to us. But I'd have all prior contact be B.C., or at least before Christianity reached the part of our world they came from. I’d have a portion of the “Lost Tribes” wind up here, in fact I’d probably name the world Arzareth as a Book of Tobit reference. I’d have the Elves of this world descend from Cain with sub divisions based on the four children of Genesis 4’s Lamech. And if I include Talking or Anthropomorphic Animals I’d explain their origin as being Genesis 2:18-20.
And speaking of Furry Bait, I want to rant about the whole “Aslan is Jesus’s Furrsona'' issue. A few different animals you can find Biblical Justification for making a symbol for Jesus, but a Lion is the last one I would chose to outright make Jesus’s Animal form, and the reason why is reflected in the Text of Narnia itself, every time they emphasize that Alsam is “Wild” it makes me uncomfortable, that sounds like the characterization of a Pagan god not Jesus.
Revelation 5 tells us what animal Jesus’s Fursona would be in verses 5 and 6.
Now I wouldn’t do the full The Lion, The Witch and The Wardrobe premise, The Passion is something that only has to happen once, and His only Incarnation is as the Son of Adam. But if I had Him appear in an Animal like form in a Symbolic Vision or something It’d be as The Lamb. He’s The Lion of Judah only as a title to describe his specific relationship with that Tribe. It would not be very relevant to mention at all in a setting with no Israelites, or one like my hypothetical here where the only Israelites came from the Northern Kingdom.And one of the elders saith unto me, "Weep not: behold, the Lion of the tribe of Juda, the Root of David, hath prevailed to open the book, and to loose the seven seals thereof."
And I beheld, and, lo, in the midst of the throne and of the four beasts, and in the midst of the elders, stood a Lamb as it had been slain, having seven horns and seven eyes, which are the seven Spirits of God sent forth into all the earth.
Now there is some debate over just how Zoologically flexible the Greek words for “Lamb” used to describe Jesus are, the possibility that they could include Rams or Goats does exist Jesus as a Goat would have potential significance to the Tribes of Joseph based on Genesis 37:31 as well as to people who are into Yom Kippur. Exodus 12:5 even says Goats are equally valid for Passover. And it’d be an amusing subversion of expectations given Pop Culture’s love of assuming Satan is a Goat, (Biblically Satan is the Great Dragon and the Old Serpent). But I'd most likely just go with a regular Lamb like most visualize anyway.