Ed Young, whose illustrations in some 100 children’s books, many of which he also wrote, mesmerized young and not-so-young readers with intricate depictions of fairy tales, poetry and his own life story as a Chinese immigrant, died on Sept. 29 at his home in Hastings-on-Hudson, N.Y. He was 91. His daughter Antonia Young confirmed the death. Mr. Young trained as an architect and worked as a graphic designer; he never intended to become an illustrator of children’s books. But a chance opportunity to work on the book “The Mean Mouse…