If I am hearing you correctly then all you have to do is set the input for each channel strip you want to use to the corresponding adat lightpipe input. ie Dig-A1,Dig-A2,Dig-B3(if your using the B input. You should then be able to use all of the channel features during your mix down. I use a lightpipe soundcard in my computer and I frequently route through the 168rc on multiple channels for effect and eq loops.
I hope this helps.