I'm not a great fan of Sago Palm. She do what others do better but why not. She is good for a great blast turn 1 against bosses.
A girl desserving attention may be
Bird's Foot Trefoil. Her 7.5x intercept sounds nice. She lacks of evasion for sure but works in a hit rate debuff team. Hit rate debuff is capped lower than evasion (70% vs 90%) but she deals more damages. She could work in some scenarii.
The challenge map is fun. Hard enough to make it a challenge but way easier than the actual stages. I was affraid of another 1+ hour stage but no.
727 is a recurrent pun with Nazuna. Like the special quests on 2 and 27 of each months. Japaneses love puns like that. I let the others give more details. I don't want to misexplain it.