Hereby I post some feedback on the 3 items published in unit 1 chapter 9
1. "I never do songs with my group of 10-year-olds. They think singing songs is for babies."
In my opinion you have "musical groups" and non- musical groups, where children love or dislike singing. I am convinced that this can be changed (in both ways). I think we teachers can help a lot, by looking for appropriated songs, using technology in class (I am thinking of karaoke on youtube), or looking for songs they like.
2. "I always start the lesson with a review of the previous lesson. And I always end the lesson with a song."
I agree, although the ending of my lessons can be others than songs, it can be a game, a story, or a video.
3."I prepare extra exercises for the children who finish early. It's not good if they have nothing to do."
I agree, although I prefer them to help other students. Ideally I make them work in pairs or groups (with different levels in each group or pair) so that they can help each other. This way the fast finishers learn by explaining, and the slower ones learn by the explanation they get. However this takes a lot of social skills and habits.