This may be Lv 100 but our characters are way stronger. Especially when phoenix is weak to Melee during tranquil stance. Even if it goes into the other stance, it’s doable if you go with Melee characters as you don’t get penalized with ranged or magic resistance.
You do not need the current awakened banners to complete this. But it’s a good idea to have those characters for the co-op for extra tokens.