I don't see anything obvious. I can't actually see how you have the switch wired, but if it's the middle lug and the one farthest away from the pickguard, then the operation would be reversed from what you wanted: split when pushed in, noise-cancelling when popped out.
I would suggest poking around with a multimeter to verify the connections.
It might be that the pots may have been damaged, if they aren't working correctly.
Regarding the possibility of the middle being out of phase with the bridge, you can swap the wires. If that fixes the phase problem but results in hum then you can swap the neck with the middle.