Honestly depends. An attack boon is preferred on her because it increases her damage, but if you're just using her as a mage tank, and no Wrathful Staff, then a Res boon is better.
As for the staff, it's mostly based on what your team needs. Fear (Atk debuff?) makes the team tankier while Gravity has more utility. Absorb is a nice option for things like Close Counter builds to make her more sustainable.