On my 2014 MCS the parking/DRL/foglight are all in one assembly below the as part of the bumper cover. By the way, I have replaced the DRL bulb with a higher power LED bulb and they work fine with no canbus errors.
My 2015 MC is the same and I don't have the foglight option The headlights stay off. The little lights in the bumper act as DRL and they are pretty bright as is. I think that is all they do because the signal light is built into the bottom of the headlight.
The canbus issue surprises me. I understand how a device could create electrical noise that would interfere with communications but generally LED components are noiseless. They are a standard component in a low noise linear power supply and are used inline for noise sensitive circuits like audio effects. The only thing I can think of being a problem would be an LED bulb that has a voltage conversion components. I haven't look too closely at the but I wouldn't think there would be enough room to fit voltage conversion circuitry other than perhaps a resistor.