Yes, I have heard the stereotype of miserly Jews. In the version I saw, what was emphasized was Fagin's criminality, not his miserliness.   

I was not commenting on the book, which I haven't read. I was commenting to point out that someone has already taken Fagin's character and has presented it in such a way that it does not reinforce a stereotype. I presume that someone was Lionel Bart, although perhaps the versions I saw were altered from the original Broadway musical.

Kent