The answers to the first thee clues are altered familiar expressions, explained by the answer to the fourth clue.

1. Feature of a clumsy dancing couple
2. Baseball team enjoying the Jacuzzi
3. Beloved Vivaldi piece on steroids
4. Even

Answers:

1. Four left feet
2. Nine men in a tub
3. Sixteen Seasons 
4. All squared up

Explanation:

The first word (number) in each answer is the square of the first word (number) in the familiar expression: 

2 (squared) left feet = Four left feet
3 (squared) men in a tub) = Nine men in a tub
4 (squared) Seasons = Sixteen seasons

Credit:
Jack McInturff