Final answer:
Idaho's state fruit is the huckleberry, which shares its name with 'Huckleberry Hound' and 'Huckleberry Finn' from 'The Adventures of Tom Sawyer'.
Step-by-step explanation:
The state fruit of Idaho that shares its name with a blue cartoon dog and a 12-year-old Missouri boy who is taken in by the Widow Douglas is the huckleberry. The blue cartoon dog refers to 'Huckleberry Hound', a character from a classic animated TV series, and the Missouri boy is from Mark Twain's novel 'The Adventures of Tom Sawyer', where one of the characters is named Huckleberry Finn. Idaho designated the huckleberry as the state fruit in 2000 due to its abundance and popularity in the region.