No, gender nonconforming behavior in children is not indicative of adult sexual orientation, because children are children, and they like to explore different types of play. A child who likes to pretend he is an astronaut will probably not grow up to be one. Similarly, a boy who likes girl's toys is probably not a homosexual.
No, gender nonconforming behavior is not indicative of adult homosexual orientation, because children at a young age are learning, and like to explore different things. There are also variations in children. Some boys are more feminine than others. That is okay. Boys and girls should explore the world around them, without feeling like they are being judged as who they will be as an adult.