"So far as I'm aware the Shade-Sybil-Hazel story is a complete VN invention. Can anyone think of anything similar?",  asked C. Kunin.

The way Carolyn expressed her question almost misled me because I began to reason following her own train of thought and, apparently, she already takes for granted that Pale Fire's main characters are "Shade-Sybil -Hazel" while I don't. Actually, it was she who brought them up as part of her own creative way of reading the novel.
Obviously the "S-S-H story"  is a complete VN invention... but so is "Pale Fire" with all its other characters, structure, poem, index inter alia.

 

She also mentioned: "...the literary foreparents  (probably there is a better word - - inspirers?) of Pale Fire include, but surely are not limited to: J&H, The Portrait of Dorian Gray, The Three Faces of Eve and the Alice books..."
Carolyn, are there direct references to "The Three Faces of Eve", or any kind of hint that might me help understand its placement among putative "PF's literary foreparents"?  

Besides, the expression "literary foreparents" ( Harold Bloom would have spoken of these as...Serifins or Cherubins?) is too strong to apply to VN's abundant references and allusions which don't affect the novel's construction in any significant way. Why not also add Samuel Johnson, and Boswell's extensive biographical commentary of him, to your list? They neither "shoot horses" nor have they "killed the cat" (curiosity was allowed to live on).