something about 不是一人能领导:)

柳亚子 was trying to flatter Chairman Mao by saying "不是一人能领导，那容百族共骈阗". It's like saying all the happiness and harmonious unity in china was due to Chairman Mao's leadership. Your translation of "No way one man can rein" is way off the mark.

And again, in my humble opinion, "火树银花不夜天" describes fireworks.