As far as the CD voices...I don't think you can drop those out without having a split track CD. I've heard of a few small recording studios that can do it, but I don't know.

As far as your mixer diagram...here's what I'd do:

Assign all your channels to sub groups 1 and 2, then do subgroup 1 and 2 out to the camera left and right and assign the subgroups to go out to the mains. I personally don't like running the mono out at the same time as the stereo outs. I'd also move the keyboard to one of the mic line inputs and put the computer on the other stereo pair. But that's just me.