The word prodigy applies to Waverly due to her being especially good at chess, or whatever it was she does. Her mother's point of view on prodigy is being the best she can be, and the term applies to her mother by not being quite as smart as her daughter.
Omnibenevolent would mean universally good. (Good to all, same meaning)
I would answer with the third option, as she does mention that she wouldn't place it in the dystopian genre, but there is no harsh criticism to suggest that she did not enjoy the book.
I hope this helps!