both still accessible to a child in a way that the surrealism of Moominpappa at Sea isn't.

This is very true, and I agree that the Moomin books - especially the later ones - are pretty surreal.
As a kid I also read a lot of Maria Gripe (no idea what those are called in English but: Tordyveln flyger i skymningen, Skuggan över stenbänken og Anges Cecilia especially). and those books freaked me out. Not because they are surreal, but because they have this veiled, strange quality. I read them and always felt I was only handed half the story and the rest of the narrative was all those creepy whispers I could barely make out from the text. (if that makes any sense)

And yay for empire Records quote. Your right - it does fit well!