Stephen King's: " pet ________"?

Questions

This composer was once accused of drawing on Beethoven for musical ideas. He replied "Das weisst jeder Esel" (any ass knows that). ?

After being left an orphan at the age of 10, he was taken care of by his older brother Johann Cristoph. ?

This composer travelled extensively in Eastern Europe to research the elements of Magyar folk-music. ?

With whom did Clara Schumann fall during her husbands period of mental illness ?

This hugely prolific composer was ill equipped to deal with the ways of the world. Despite the aid of friends in having his songs published he dies in poverty at the age of 31. ?