This shouldn't even need to be discussed, but the Stadium need to be in Super Smash Bros. Crusade. It has been a staple since debuting in Super Smash Bros. Melee and it should be in this game as well. Super Smash Flash 2 is implementing a stadium. Let's not get left out of the wagon.
For the games I was thinking Multi-Man Crusade, Break the Targets, Board the Platforms, and Home Run Contest.