These are the characters that can be unlocked through special means. All of their abilities, as well as how to unlock them, is displayed under the character's name.

Weapon: Dual Swords, Dual Pistols
Abilities: Sharp Shooter, Double Jump
How To Unlock: Collect all Deadpool Bricks

Stan Lee
Weapon: Web Blasts, Goldie
Abilities: Superhuman senses, Web-slinger, Big Fig (Stan Hulk form only), Goldie
How To Unlock: Save all Stan Lee's in Peril