I think his situation is interesting in that he is essentially an orphan making his way in the world. And as you say he is our window into the world of Shakespeare and Essex and the others. Clearly he has to be able to sing, act and move well or he couldn't be a player. But it would make him seem a little more human if, for example, he could have been sea-sick on the ship, (as Nicola is) or made a few mistakes when he first joined the players. He is an eleven year old boy after all, and I don't know any eleven year olds that perfect!