@Chicago_SH 

So If i understand this correctly, you don't need a special companion switch or something. Just replacing the normal 3 way switches from Kasa you can continue to use the mechanical switch  for the 3rd location in a 4 way config? 

Has anyone tried 4 way with KS230 3 way dimmer switch?

This is how I feel. I want all of my switches to look the same. Each of my switches (5 of them to control one light) are all located on a 3- or 4-gang switch box, so having one of them different drives my OCD nuts. Don't like it at all! I'm going to try to make the 2 switches that are not on the ends of the circuit not part of the circuit, so I can have a 'smart' switch that triggers the 'actual' switches via automation. Hopefully that will work.

@board4mic I have this setup and it works for me. I REALLY wish there was a four way switch to replace the dumb switch, as I want all my switches to match. 

@board4mic 

thank you for the diagram.  Did you replace both 3-ways with Kasa 3-way switches or just one of them?  Did the system know if the lights were on or off?  Did the scheduling function work?  Thanks in advance!

OK I am looking at an original 4 way setup with one switch having the expected 4 way wiring, one has the expected 3 way wiring, but one has what looks to be a 3 way switch but wired in a different way. There is the expected black, black, red but with an additional black on the line side. It appears to me that the 4 way switch is at the start of the chain, the 3 way with the additional black wire is the middle, and the last is the standard 3 way. The additional black is power out to the last 3 way? Is that possible? Anyone seen this setup before? 

I have installed two kasa on the 3 ways, combining the blacks as they were originally. The lights work but depending on the on/off state of each switch, the other switches don't always work. 

Any suggestions?

@spatical brilliant.  Thank you.