She scratches a letter......

Narrator (Conrad) and Sally.
I think that they are dominated by ego in the beginning of the book because when the cat comes they just follow him around and don't try to stop him when he is messing up their house and wrecking everything.The kids just watch in aw as the cat runs around. And they choose to listen to the cat instead of the fish. In the end of the book they become dominated by superego because they start to listen to the fish and make him clean up and leave the house before their mother gets home.

The Cat.
The Cat starts out as dominated by id because he just walks into the kids house and makes all kinds of mess all over the place. Like when he brought in Thing 1 and Thing 2 who just ran wild or when he ran around the house with Mothers dress on a kite. But in the end he feels bad after Conrad yells at him and makes him clean up all the mess that he makes and he becomes dominated by superego and gets everything clean by the time Mom comes home.

The Fish.
The Fish is dominated by superego because the whole book he was talking about how the Cat was a bad hat and that everything was a bad idea. The whole book he was a kind of babysitter to the two kids and trying to help them get rid of the Cat before their mother got home.