However I believe you can follow any of the Gen2 diagrams marked (with Neutral). It is my understanding that this dimmer requires the neutral to work. My installation has a neutral so I never tried it without the Neutral.
You can have a Smart switch on one end and a dumb 3-Way on the other. The dumb end can turn the light on and off but cannot change the dimming level.
OR
You can have a Smart switch on one end and an AUX control on the other. The AUX end can control the on/of and dim. There will be no status LEDs on the Aux switch.
I decided to try it anyway and it works fine. In case anyone else wants to try, just follow the last wiring diagram on the LZW31-SN instructions (for two smart dimmers).
For Gen1 dimmers, we must use association groups 2 and 3 instead of 2 and 4, since group 4 is not available on Gen1 devices.
I also tried a LZW31-SN controlling a NZW31, but I could only get it to send on/off commands, dimming wouldn’t work.