Got it. So the thinking is that the rain sensor was in series with the common (white) from the valves.
Multiple questions and thoughts below. One of them might help isolate the problem. Agree this is strange. Although the picture does not show it I am assuming all the blue lights are on, on the rachio controller.
Where was the orange wire coming from on the rainbird that now is black on terminal 4 of the rachio?
Do you have a voltmeter that you could measure the voltage between white and the other wires? Should be 0 both AC and DC on all wires.
When you tested ONLY white and green I assume all the rain sensors wires were also disconnected?
If not
I would suggest removing all the rain sensor connections and see if the rachio works.
If so
How could you tell the other zones were active with only the green wire connected?
Hope this helps