I can't comment on channel cats, but I can say with 100% certainty that carp (also bottom feeders) do detect line, and also have very sensitive mouths.
I've watched carp in clear water as they avoid one bait attached to a heavy, visible line, and moments later readily suck up the second presentation only a few feet away from the first, that was attached to a light, low-vis leader.
I've also watched carp suck up baits attached to large hooks and immediately spit them out, while sucking up and swimming away with (without spitting out) baits attached to small hooks on a slack line. The difference in this scenario is that they didn't detect the unnatural presence of a large hook, and didn't feel the tension of the line.
Again, this is my experience from carp fishing, but I would try applying these principles to cats:
1) leader they can't see
2) hooks they can't feel
3) some slack in the line, so that you can set the hook before they detect the line and spit.