Motion sensor to integrate with wemo smart plug (WSP080)

Hello all! I so appreciate the discussion here! As a newbie it's been enlightening read (as the conversation unfolds) and learn more about the opportunities (and potential problems) of working with zigbee devices. I'm still planning to move forward with the collection of devices I have ( Motion sensors to turn on an outlet that powers a water pump - #2 by Colin ), but now I'm wondering if I should install cat5 (cat6?) drops in each room of the apartment I'm renovating. Perhaps keep the WiFi router in the attic and branch off of it to the wall jacks (via conduit)? Would this reduce the significance of WiFi interference with my zigbee network? Also, currently the walls are stripped to the framing (plaster/lath disposed of). Wondering if there is any "shielding" I might install to minimize outside wifi interference. Googling around seems to indicate that foil backed insulation board may "kill the transmittance of cellular or wifi signals throughout your home. It can even block signals between adjacent rooms." Has anyone had experience with this? Many thanks for your help!