Rekordbox works perfectly fine as well with my Audio 2 as my Audio 6.
You just have to get the settings right. in the case of the Audio 2 you got just 2 channels anyway. I can't understand how that could be a problem to be honest?
What exactly is your problem? I mean the settings explain themselves...
And the manual is good as well. Just take a look in it and read the chapters with audio routing