
I have kind of mixed feelings about John Birdwell. He's a nice guy, funny and lighthearted, and his guitar playing is fun as well, but he's such a horrible parent! I mean, if someone has Yumika as their mother, they'll need a really good father, and instead of being that good father, which John could have been as far as I can tell, he just neglected Chance just as much as she did! I know he's a busy person, but still…
About the team to stop Naoki, I think you accidentally left out Jean ^^. And Yuzumi, but she stated herself that she wouldn't be in the team all the time since she was too busy with other occupations, but that she would help them whenever needed. I wonder what her "other occupations" are… Do I want to know?
I absolutely loved the episode where Chance was the main character and you got to see his whole life story from his point of view, including Mana-chan being real

As for the ages, I think it was mentioned somewhere in the beginning that Kitti was 16, which means Washa, Yuuna, Yuuma and Yuzuki are all probably around that age as well. Jean is probably only 15 since she skipped a grade at a young age (which is kind of funny since Washa looks 12 and Jean looks about 17 when actually he is older and she is younger ^-^). Since Naoki and Chance are a year above them in school, they are probably a year older, which is confirmed by the episode 4 quote that Piefan found.