"Haachama"'s second form can insta kill anyone but Calli, so she can carry the role of healing and resurrecting with items when needed, while Ina can focus on Magic attacks and whenever her Tp is enough, use Tako protecc
Gura can easily cheese the first form, same for Kiara (with her counter skill) but later on the 3rd phase is purely magic attacks, so gura could have a hard time then. Thus I suggest using Calli, Ina, Kiara and Anya, putting Ame in the 5th place, so you use Anya's ulti on Kiara, so Ame enters the battle (preferable with a gun to use her ulti)
That's just an idea, maybe a little late, but hope you get throught it!