Ooh, lovely! It's very unique and pretty, and the pronunciation is gorgeous. I personally love the way it's spelt, but it may cause a few pronunciation issues in the future...though I wouldn't let that deter me personally. Nicknames could include
Nonie, Eenie and
Nina.
If I used it, I might balance it out with a more "normal" middle name.
Oenone JosephineOenone ClaireOenone RebeccaOenone AnastasiaOenone OttolineOenone Lillian Sophia