all the bigger mixers on ebay that you posted only take the stereo left + right master channels or one of the sub group left + right channels and send that to the computer. the r16 and r24 are 8 channel at a time audio interfaces but dont have the routing power of the biger mixers. i have the r24 and it does have eq's for each channel but only phantom power on channels 3-8. one nice thing that the zoom's have is being able to have a meter for each input. but if you need the bigger mixers for live mixing i would go with the allen and heath. hope this was helpful.
basses:modified fender squier j bass, custom built 4 string, rogue 6 string, kremona gibson bass, Eminence 5 string EUB