i'm not sure how u evaluate over skills/hp/atk.....maybe i'm a noob myself but my setup is as below and i would really like Amaterasu in my team, her atk/def down is better than sniper shot...with that i can free sniper shot from my Soul and get a better skills(example Dullahan required maiden's prayer to remove the death debuff otherwise u need to get a specific Hime just for that which dropped the ur damage more severely, i'm using Belobog in my dark team for that....so u can imagine...a light hime without weapon skills nor eido effect...)
i tried to swap SSR HP to SR ATK and guess what, the damage is nearly the same from 13k-17k per hit so why not having more hp with additional burst effect? by the way, they are all skills 20
I have Echidna 1 star but she is not even fit into my list, i tried it last time and she disappointed me...
Dullahan is backup when i needed more hp > atk