Has anyone been able to define well or measure differences between vinyl and digital?

Vinyl sucks.  Measure that

I think it is the physics of analog crosstalk of the cartridge :)

Ps Audio recently posted on this very topic. Perhaps the answers you seek are contained within Paul’s posts. 

"An album with DR 6 doesn't necessarily sound overtly bad. And an album with DR 12 doesn't necessarily sound good (but the DR isn't to be blamed at least). For rock/metal a DR of 8 and above is considered okay. Electronic music can still sound okay with DR 5 because it is less dense."

Ref: https://dr.loudness-war.info/faq

It therefore seems the differences are mainly academic in the same way as ASR tests hardware.

If you don't like listening at 90dB then something with higher compression might even sound better. Indeed the average person seems to listen around 70dB for comfort.

Is the impact of 2 channel speaker systems equal for either source?

Regarding Atmos as a multi source format, I wonder how robust it is vs say binaural recording playback. My impression also is that Auro3D is more ‘immersive’ and therefore more accurate in capturing natural environments. 

Oth ambiophonics offers another method of playback that reveals the power of certain types of immersive systems.

Ambiophonics reference