No. Camilla's children are invited to many royal events but they are not official royals. They did not become royal when their mother married Charles. Camilla's children are private citizens, and they are accepted by the royal family, being friends of William's and Harry's. They are not automatically invited to all events, but they are invited to some. Being invited to Trooping the Colour doesn't mean a balcony appearance, either, and, perhaps, Tom and Laura don't want to appear on the balcony.
The royals invite many people to events that the general public do not know about.