"Something I am aware of that you didn't
bring up: Pre-emp/De-emp."

I did bring it up but only in the context of the playback quality - that is if there is an error in decoding.

The pre-enph and de-emph is not quite like Dolby. First of all it is either o or off, and it is designed to turn on and off transient free during playback. It is a command on the CD itself, there is no detection of level or spectral content like in Dolby or other noise reduction systems.

And actually it is not really for noise reduction. When the source has low HF content it is not using enough bits and people complained it sounded grainy or whatever, some such adjective. This was before CDs actually, it is built into all CD players, unless there are some that are cheaper than even I can imagine.

Then, when it came to totally digital sources they actually had to add noise, called dither, to make the low level HF sound right. They may use the pre-emph on that at low levels at all. But there was never any need for noise reduction because there is no noise. In fact, when they did the old AAD disks which were from the master tapes from back in the 1950s ad such, the tape hiss provided the dither and I think the quantization process actually removed some of that hiss without having any effect on the frequency reponse..