“Angels were created as His hosts and obligate servants (the biblical word used is closer to a “slave”), as God’s messangers (aggelos), not His “fans.” “
That’s not quite true. Job 38:7 (”When the morning stars sang together, and all the sons of God shouted for joy”) places angels singing God’s praises before the creation of man.
What were the MULTITUDE of angels doing in Revelation 5?
Did I say the angels were created after man was created? I simply said they did not exist before time existed, i.e. "zillions of years" in Harley's parlance. However, angels did not exist before Creation. As to how soon after wards did God create man is a different story.
Your verse also says nothing as to the actual timing of the angels singing praises...except that it was after the formation of the earth. So, I take it HD believes in evolutionary time scale when he says "zillions of years."