I disagree with the first statement. Everybody likes singing and dancing, i think it's a good way to teach new vocabulary in order to motivate students to talk and sing. Of course, teacher has to focus attention on student's likes.
I agree with the second statement. All the time, the lesson needs to recycle vocabulary of the previous one. I always start the class with a game, recycling words or grammar, and sometimes finish the clases with a song or with a short and funny activity.
I agree with the third statement. Always give extra activities for the children who finish early. Sometimes, I allow them to be helpers, they encourage the others and in the same time guide them to find out the answers.