The way my outside garage lights are wired for the 3-way switch, there is a white or neutral wire that is accessable from within the garage, but not in the house, so the Kasa switch set will not work. 

Wemo however sells a single 3-way switch that will do the job (see attached picture). I have a house full of Kasa/TP Link products that I have set up with schedules and through Alexa and I love the way it all works together, so I really do not want to have to introduce another product brand into the mix.  Do you ever see Kasa selling a single 3-way switch the same as the Wemo smart wifi 3-way light switch (model: WLS0403-CA).  This makes more sense than having to install 2 wifi switches to do the same job.