I'm wondering if a combo of "1" and "3" would work better, but change the cap and resistor for "1" to a cap of 100V or more, and a resistor of 1/2 to 1 watt? I'm pretty certain it may just be the cap that is at fault here on "1", because it's voltage rating is too low; you may also want to increase it's size, depending on what you see on your scope. That's all just a guess, though, on my part. My thought is that it is with the pump (not so much the relay); when the contacts open, you are getting the flyback voltage from the pump motor, giving the spike (have you tried disconnecting the pump from the circuit and see if you still get the spike on your scope?), so doing something to dump that spike is needed (ie, snubber). I also wonder (though I don't know if it would be to code or cause problems otherwise) if you connected the "floating"/unconnected relay contact to -ground- instead of neutral (maybe with your #3 snubber?) if it would work better/worse? Maybe someone can correct me here if I am wrong about this suggestion...