Any combo of choice leading into 6B will work on the necos as long as Ciel is not close to the wall when performing 6B. So any combo starting mid-screen should not be a problem. If a combo starts in the corner, you would need to forgo the 6B and cut the combo short.
The problem is that the necos will both bounce off the wall more than other characters for whatever reason (or looks that way because their hitbox is smaller), and Ciel's 236[A] needs to arrive to the necos AFTER they have stopped moving away from the wall after the bounce, which cannot be done anything about near the corner no matter what.