Is your Pioneer HDMI compliant, if so what spec (1.1, 1.2, or 1.3). The CAT5 cable is an ethernet cable for internet connectivity that you would need to upgrade your firmware on any hardware that supported that feature, why you would need to prewire it into your setup is beyond me. Some hardware, like my tv, gets firmware upgrades via an external USB device rather than a direct connection to the internet.
If your receiver is HDMI compliant I would run HDMI out of the BD player to a HDMI input of your receiver, and then run another cable from the HDMI monitor out to the HDMI input on your television. This is the optimum set up if possible.