even though "3 may be able to have it" means that 3 people may have the ability to use it pretty much suggests that there will be another person in the manga that can use the ability. Why would kishimoto write that if it had no significance? If no one other than Sasuke and Itachi would actually possess the power? I am pretty sure it will not be Kakashi, but it just might, you never know. I hope its an uchiha girl that gets it.