Trivia: In one scene Daffy suggests the team name the Ducks. Bugs then responds, "What kind of Mickey Mouse organization names a team the ducks." This refers to the 1992 Disney film "The Mighty Ducks."
Trivia: When the aliens first go to steal the talent of the NBA players, there are two fans in the stands with about a minute of screen time - the first is Patricia Heaton from "Everybody Loves Raymond", and the second is Dan Castellaneta - the voice of Homer Simpson.
Trivia: The gym where the Looney Tunes characters practice is called the "Schlesinger Gym" - a reference to Leon Schlesinger, who was the first producer of the Warner Brothers cartoons.
Trivia: After the Monstars steal the talents of five NBA players, the NBA suspends its season fearing an unknown contagion could be affecting its players. This ended up becoming a reality for the NBA in March 2020, as the NBA indefinitely suspended its season following the discovery that Utah Jazz All-Star Rudy Gobert (and later his teammate Donovan Mitchell) tested positive for COVID-19.
Phaneron
Suggested correction: Both of these people were also credited in the film for their appearance, so this wouldn't be trivia.
Bishop73