The challenge here is that it will be pretty difficult to identify exactly which of the dozens of + and - wires are powering those CO detectors. 
This is especially because I can’t use the CO detector zone and C wires to trace the power wires, as they are not coming from the same cluster of wires.
If it’s critical that I find and disconnect the CO detector power wires from the panel, I’ll try to find them. Please let me know if it’s ok just to leave and forget about them. 
Also, Jason, can you please help with my question here? Thanks.