How do I set up a field recorder with camera/wireless monitoring?
Easiest bet, use a distribution amplifier.  If you need the same audio to both, a DA will boost the signal so that it can actually go to both.  Not sure what the inputs on the Comtek are though, the DA will generally work best if they can both take XLR in.  Also, are you mixing in stereo?  If not, do you need two XLR to the camera?

As for the cable to the camera, you could heat shrink wrap two XLRs if you can't find a basic 2 channel XLR snake (assuming you are looking to have only one "cable" going to the camera.  Any reason not to timecode sync them and combine in post if running two cables is really a problem.