You last photo, which shows the solenoid writing: what type of plugs are you using at the end of the gray cable? The image resolution is pretty low so I can’t tell. It seems I can only see two solenoid wires that go to the plug, I can’t see where the other solenoid wires went. Did you try to connect the two wire from a solenoid directly to the 24VAC transformer wires, and see if that activates the solenoid? As I said, if you measure 28VAC between COM and zone 2, and you have a solenoid connected between COM and zone 2, it doesn’t make sense to me that the solenoid doesn’t activate. That almost certainly suggests there is a wiring problem.