I miss the Denon MC6000 mk2 in your line-up. By far the most compact (19″ form factor), best build (when they say “built like a tank, you can take that literally) and now fully Serato supported.
It ticks all of your boxes I believe. 4-deck Serato control, fully stand-alone (matrix) mixer.
The lay-out has improved a lot since mk1, as has the soundcard (now 24-bit). The jogs, albeit it of the smaller variety (many controllers have this size by the way), are excellent. I just sold my mk1 which I used hard for a few years (since it came out in 2011) and I sold it “as new” because you couldn’t tell it was used. At the Frankfurt Prolight+Sound fair next week I intend to visit the guys at the Denon booth and get me a nice shiny mkII. I had to play a few gigs without it and with another controller and I missed my good ole 6000.
Greetinx.