I have the same setup and it’s pretty great IMO. If you get a copy of Traktor Scratch the dn-x1600 has a built in Traktor sound card and the SC2900s work in midi-hybrid mode as they call it with Traktor. It’s a bit of a pain to setup, but it works and you can be into the world of using software with just that.
The X1600 is also a full MIDI mixer so you can assign traktor controls and sliders to it if you don’t want to mix externally (not sure why you wouldn’t, but there you go).
Worst case is you really, really need performance pads beyond the hotcues, but you can just go buy a Kontrol F1 for $200 and you’re set.