I know this is an old post but I just wanted to note that mpxc is correct. I had this same issue. You need to remember that each character placed into the level is an instance and you can edit the collision on each instance of the character.
I know this is an old post but I just wanted to note that mpxc is correct. I had this same issue. You need to remember that each character placed into the level is an instance and you can edit the collision on each instance of the character.