Eve is pretty straight forward, just go pure attack.
Isarnia is a little more complex, especially if you get her costume.
Some questions: do you use isarnia only for titans or also for raids? is isarnia on your defense team? and do you use her primarily for damage or for her def debuff?
I don’t have her costume, use her on my defense team and use her mostly for her debuff. I have +18 on her and hedged my choices by scaling up both her def and her attack. I think in this way she doesnt contribute the highest possible attack damage to tiles on titans but she is also not squishy and can survive long enough to be a gamechanger in raids.
If you use her only for titans, go pure attack for the tile damage.