Tolkien and Chesterton make it into Wilson's salvation tent, because he says their entrance does not depend on "doctrinal works." All the best trying to understand the tortured logic.
Everyone is saved by faith. That is the message of Jesus to Nicodemus in John 3:13-21. Was Nicodemus saved in John 3? No (John 3:11-12). When Tolkien and Chesterton don't trust in Christ alone for salvation, because they're working for it, they are not saved. Their doctrine of works condemns them.
You (Y) apply Wilson's logic to a Jehovah's Witness (JW).
Y: You believe Jesus is God?
Y: That's OK, because salvation doesn't come through having right doctrine. It comes through believing.
JW: But I don't believe Jesus is God.
Y: That's OK, because you are not saved through an accurate doctrinal statement, and that's a good thing, because your statement about Jesus is wrong. Good news, however. You can have your doctrine wrong and still be saved, since the doctrine is a work and we're not saved by works.
JW: Even the doctrine of salvation?
Y: Yes. You can have the wrong doctrine of salvation and still be saved since doctrine is a work and you can't be saved by works.
I gather that the written works of Tolkien and Chesterton so smack of God's grace that they were saved by grace even if they didn't believe. Their doctrine doesn't smack of God's grace, but their writing does. More and more join the evangelical fantasy salvation league. Fewer and fewer actually saved.