Team 9 certainly must get along well in the night. Come to think of it Cirno's element ice thrives best on coolness of night. Mystia is a night sparrow (so I've heard) & she'd be active at night. Wriggle's last name obviously suits the night-style well, along with bug's liking dark hiding places with the dew that gathers. Rumia enjoys darkness for reasons I'm unsure of. Maybe, the element of surprise is her game. So of course they're all happy.