Just to set the terminology straight (yes, I’m like that!):
Channel == track
Subchannel == column
You can always mute and solo a track and/or it’s columns, but it’s entirely on a GUI level. I think the shortcuts are CTRL+numpad 1 through 9 (check out keyboard preferences for column shortcuts). You need to automate the volume, or a gainer, to achieve the same result, but with pattern commands.
As for muting/solo’ing instruments: +1, would be very useful!