Lewis himself would have urged a great deal of caution in trying to attribute this or that characteristic in a writer to this or that - APPARENT - influence from his background. I have cousins who had the same parents, attended the same schools, had the same ethnic and neighborhood background, who express very different POV from each other. Better to focus on the actual writings of Lewis, rather than the 1000 incomplete, misleading, often contradictory theories about what influenced him this way or that.
The best guide we have would be his autobiography, Suprised by Joy, and even that is no doubt incomplete, partly because he said he had to omit certain material, and partly because no one totally can see what influences him or her.