These are the three costumes unlockable in the game.
Finding enough of the relevant outfit statues hidden in the game will unlock a Challenge Room accessed via the Bonus option from the Main menu.
In the challenge room, you will fight against Wolverine in the ‘attire to be unlocked’ and once you win the battle, the costume is available for use in single player campaign.
The costumes are nicely detailed, but they don’t appear in some pre-rendered cutscenes, which is a small issue nonetheless.
I also noticed that you will still come across these statues in later stages even if you have found them enough to unlock the Challenge room in the beginning. While they offer no additional costumes, finding them gives you experience points for you to level up.