IMAGINARY FRIENDS
There is a classic 1944 movie-available on DVD- that also has a little girl and an imaginary friend {only one}. "It is "Curse of the Cat People" by the noted producer Val Lewton. Don't be put off by the misleading title.
Unlike "Opal Dream", is has more a fantasy, even fairy tale, plot. But it too captures the dream-like aspect of having an imaginary friend.
It seems to me that Kellyanne's "retreat" to an imaginary world is a reasonable response to her situation. A shy and sensitive child she lives in a crude world that itself is driven by fantasy. The men who dig for opal are themselves engaged in a futile and fanciful pursuit of wealth. Kellyanne's father sacrifices his own family's well-being to seek windfall riches. In such circumstances, Kellyanne's make-believe world is a plausible response to the irrationality of the adults around her.
Blaine in Seattle