I would do two gang for everything and then a single gang mud ring for those that you only need the single gang. That was you can more easily expand if needed.
With a two gang mud ring, current Inovelli switches and dimmers are incompatible side-by-side. I assume it will be the same for these.
The bigger issue is that I’ll be finishing before the devices are available and don’t want to be redoing drywall after finding out I need to switch some one-gang boxes to two-gang. That would still apply if I need to switch mud rings.
Oh right, I believe I was the one who actually discovered that. I used a file and just took a millimeter off the mud ring, and then they fit. Not an ideal solution, but something to consider.