I may have misinterpreted your goal of monitoring the “health” of the circuit. You are correct, the example I provided uses the IDC5 module to check for presence of the 24V supply.
If you want to know the status of the E-stop button, the signal into IDC5 module could be moved to after the E-stop button
If you want to know if voltage is being provided to the relay, the signal could be moved to after the momentary button.
The point that I was illustrating is that the module should be in parallel with the K1 load, not in series with it.
If you absolutely need to know that current is actually flowing through the relay, a current sensing module could be used, or a resistor could be added that would not drag down the relay voltage to unusable levels. The SNAP-IDC5 requires 10V to trigger, which would only leave 14V for your relay and is probably below the pickup voltage. However, a SNAP-IDC5D module only requires 2.5V to trigger, which you could safely steal and leave 21.5V for the relay. Something like the below:
Along the same line of thought, if you want to stay with the SNAP-IDC5 module, you could switch to a 12V relay, and size the resistor to be equal to the resistance of the relay.