I've looked into this in some detail this morning.
I've used a massive online resource that Kate uses and found twenty-seven links to the major reference works containing Eugene Gladstone O'Neill. Using the crossword spelling brings up nil results.
Yet if the variant spelling is typed into Google, a handful of obscure hits do appear in the first dozen or so pages. Nevertheless, I can't understand why she would have chosen the variant spelling as it's not sourced from any authoritative reference work and clearly appears to be a misspelling.