My answer to How do I refer to aliens in a space opera novel?
Answer by Desmond Last:
I write science fiction. Science Fiction is more enjoyable when it has the possibility of truth and possibility
I believe that our Universe is inhabited by other humans. I could also say ‘I know that humans exist on other Planets’ but nobody would believe me so I do not.
How could a biological system that is perfect be anything other than the ‘only system’ that supports life?
Therefore the only question are we the first human beings in the Universe or the last?
Are we to rid the Universe of Evil or are we to destroy ourselves with Evil?
On that basis I would use the human form in your Rock Opera.