I'm currently running Mordred (EX: Sniper Shot), Poseidon (last SSR kamihime ticket), Gabriel, Shiva, Sol. Poseidon and Triton are somewhat interchangeable. Shiva doesn't help much in an auto-attack setup. The debuffs and Sol are what carry this group in most content. The synergy of Sol and Jorm without an ATK debuff cap is the key dynamic in my group. Water is capable of one of the tankiest builds in the game (Cthulhu, SSR Nike, Snow Raphael, Sol), which is what I'll be building towards for when the ATK debuff cap hits. Run Andromeda (EX: Black Propaganda) with that and you'll have an auto-attack build that should be as close to unkillable as it gets.