I don't see kakashi as much as wb asuma though. Over 5 months of being capable of doing trial breakthrough, I managed to get him freely by piecing him.

I find that if you want the semi-vanilla and not vanilla ninjas (konan, wb, sage naruto) you see them in trial breakthrough while ninjas like zabuza, baki, sound 4 are present in the 12 trials. Of course, in trial breakthrough, you receive less than 4 frags depending on the ninjas and max 30 frags in the 12 trials.