I was looking for an answer for 3-way motion as well. I'd like it smart though since it will be for the entrance lights, where I don't want it to be sensing motion/turning on during the daytime (program with IFTTT?).
Since the 3-way dimmer is only required on one end, can you pair the Kasa motion sensing with a Kasa 3-way dimmer? Does this work??
Edit: Can the 3-way be the dumb switch.