Thanks! It definitely seemed like wiring with the 12-3 romex between switch boxes opens up the most possibilities, even using a standard 3-way “dumb switch” as a fallback for one or both boxes.
Looking at those wiring diagrams again, it seems like the 3rd red traveler wire isn’t even needed in some cases, like the 2 Inovelli switches wired as a 3-way. The only cases where the terminal labeled “traveler” is connected appear to be when using 3rd party “companion” / “Aux” switches. Of course, those wiring diagrams are all for the 2nd gen “Red” and “Black” series… which I’m making a huge assumption about being valid for the unreleased “Blue” & “White” series switches, because they may not fully apply. If this video is any indication, perhaps the caveats / limitations wiring up 2x Inovelli switches in 3-way w/Neutral mode may no longer apply to the newer series. 