One thing I will say is that i use a 20 channel folio for my Supernova to listen to what is going one whilst playing via midi sequencer.
But I've found it the best solution to have a set of stereo out's connected directly to the stereo inputs of the soundcard. This gives the cleanest signal between the hardware and the computer, so any samples/loops recorded in are of the best quality with the least noise.
This sort of question is all down to how you wanna work really, you gotta ask yourself what you want to achieve, and what's the quickest way etc.
The mixer you mention looks good, although mixers are defo not an area I know too much about, so otheres would probably give better advice.