Fagin's depiction is definitely marked by antisemitism, but it is a rather careless, traditional antisemitism rather than the malignant forms we are more used to since the Nazi era.
Dickens based the character of Fagin on a real Jewish fence named Ikey Solomon, who was tried at the Old Bailey in June 1830 (he was not, however, sentenced to death). This contemporary reference, and the general antisemitic assumption that Jews were particularly money-grubbing, scheming, and dishonest, would have made the choice natural to Dickens on an unconscious level.
However, when the unpleasant aspects of making Fagin a stereotyped "Jew" were pointed out to Dickens, he felt revulsion for his carelessness. The wife of a Jewish associate criticized him in a letter in 1863, calling the caricature of Fagin a "great wrong." In response, Dickens wrote that "There is nothing but good will left between me and a People for whom I have a real regard and to whom I would not willfully have given an offence."
Dickens thus began revising Oliver Twist to play down Fagin's Jewishness. He cut many references to Fagin as "the Jew," and in his public readings refrained from delivering Fagin's lines in a stereotypical way. He also put a wholly admirable Jewish character into his 1865 novel Our Mutual Friend, Riah, whose behavior towards younger people is the precise reverse to Fagin's behavior towards his young thieves.
Interesting you should bring up white slavery during a discussion about Charles Dickens and Olvier Twist, a story about an orphan in a workhouse who narrowly escapes becoming a chimney sweep (which deformed or killed 4-year-old boys, yet they still had to beg in the streets for food). Dickens sympathized because he'd spent time as a boy in a workhouse.
Scrooge: Are there no workhouses?
Philanthropists: Many would rather die than go there.
Scrooge: Then they'd better do it, and decrease the surplus population.
The practice of child slavery in the factories was also taking place in America, and those kids have descendants living today.
If I had to guess, my bet would be the children who will lose teeth in 2010 in the Appalachian Hills cause their parents can't afford milk. Of course, children weren't the only people destitute enough for slavery. Under the Poor Laws, the poor were auctioned off by the workhouse to the highest bidder to work in exchange for food and shelter. http://www.rootsweb.ancestry.com/~pasomers/poor.htm
They were worked until they collapsed, beaten and made to work more, and fed barely enough to live on, cause it would be cruel to let them starve in the street.