Phantoms

It would be better to get % total damage I would think since our attack is sort of on the low side, I'm not sure how it works with cross surge

Cross Surge is 100% Total Damage, and Priere d'Aria is 30% Total Damage (or 20%? Did they unnerf it?). Phantoms already have enough total damage. It doesn't matter how much attack you have; % attack is a multiplier (on a multiplicative component of the damage formula, I might add), going from 0% to 15% attack is always 15% more damage regardless of whether you have 100 attack or 1000 attack.

Additionally, Ignore DEF will do nothing to help you on physical resistant bosses. Physical resistance and PDR are two different things. The only way for a Phantom to do more damage to physical resistant bosses is to raise your Insight.