First Controller

If you have ableton and a launchpad I fail to see why you need a controller rather than a second launchpad or Midi Fighter or TouchOSC or whatever….

I am sorry then I cannot help you, as this would mean that I would have to use ableton like a “normal DJ software” and that is just something I would never do or consider doing. But from the controllers you listed if you want “standard” the Mixtrack is prolly the choice.

I would not, because I like the traditional style of DJing, just with digital gear.
Ableton can do that, but it was never intended to do that.
Ableton has a totally different workflow (or intended workflows) when DJing live. I think I might try that sometime, but I do not think that this workflow would work with any usual controller and I probably would go for launchpad or midi fighters.

The usual suspect DJ softwares rather cater to the traditional style and I can still have ableton running in the back to trigger stuff with my TouchOSC.