GOOD NEWS! We have an article to help with that!
https://thedailyneopets.com/battledome/faerie-abilities
Those abilities highlights with Yellow are the recommended abilities.
For Level 10 our guide doesn't have a highlighted ability, probably because it's up to you, they're all pretty equivalent to each other. I have the 'meh' ability for level 10 because I tend to focus on defense.
Otherwise, I would recommend following the Yellow-highlighted abilities as laid out in the guide. But feel free to diverge if you feel like it.