Misc: What is a group of flamingoes?

Questions

Who was rumoured to have poisoned Mozart?

What noted author wrote: "George died on July 11, 1937, but I don'thave to believe that if I don't want to"?

Whose Ninth Symphony is universally known as the New World?

Which Beethoven symphony bears the opus number 125?

Who penned this line in a 1956 song: "Roll over Beethoven, and tellTchaikovsky the news"?