#3. "RE: Rear curtain sync with cowboy NPT-04 wireless trigger" In response to In response to 2
Ok, since you're willing to go manual, I expect you have you tried setting your commander mode to manual and the remotes in manual, while setting your 560 to S1 mode? I'm assuming that puts the 560 in dumb optical slave mode and there isn't much for the flash to think about in that scenario. So if you have rear sync set on the camera, there will be no signaling flash until it is time for everybody to fire.
If the 560 doesn't behave in that scenario, then yes, the inexpensive radio triggers should work for rear sync if everything is manual.