If you consider Huck as the main representation of children in the novel, he represents innocence in the way that he originally really wants to allow the widow to have some control over his life, he wants to be obedient even though it pains him and goes against some of what he thinks is best for him.  He also struggles to go against the wishes of his father both mentally and physically when he is locked in the cabin.  In this way there is a great deal of conflict about who gets to control children and why.

There is another entrance of the controlling adult when the king and the duke take over for Jim and Huck, even after they have achieved a certain level of independence.  In terms of victimazations, you can also look at Huck and Jim as both playing the role of victims as Jim is sold back into slavery and Huck is attacked by a variety of people and all of them looking to take advantage of him in certain ways.