The Southern Congressman that says "This hare must die!" and Bugs Bunny's comeback "It's a joke, son, ya missed it!" is a reference to a catchphrase of "Senator Claghorn", a movie character played by Kenny Delmar. Senator Claghorn inspired Foghorn Leghorn, and to some degree, Yosemite Sam.
Bugs' rallying cry, "Bugs Bunny was Here!" is a play on the WW2 era slogan, "Kilroy was Here!"
The Times Square clip is from 1937, based on the movie marquee advertising "Make Way For Tomorrow" at the Criterion Theater.
Bernard "Barney" Baruch was an American financier and statesman. He was very well-known and often walked or sat in Washington, D.C's Lafayette Park and in New York City's Central Park. It was not uncommon for him to discuss government affairs with other people while sitting on a park bench. This became his most famous characteristic.
One of a handful of Merrie Melodies shorts that feature live-action scenes. (The initial shot of Times Square in New York, and the shots of the Army deploying.)