The idea of two new elements for Donkey Kong and Bowser were considered. A Bananas Element for Donkey Kong was considered, however, how it would fit with other characters other than Donkey Kong and his family and for future use wouldn't have made sense.
For the Wii and Wii U versions of the game, other Nintendo characters which were considered but were ultimately disagreed upon were Warrior Princess Peach, Kirby and Fox McCloud. Nintendo said no to the idea of Warrior Princess Peach as it would seem out of character for her, as well as any other hero Mario characters were off-limits. For Kirby, as he was partially owned by HAL Laboratory, Activision were unable to get the license for him. With Fox, Nintendo thought that having him in the game would've pulled interest away from Star Fox Zero which was soon out for release.