How to edit the Plist so as to remove all reference to wireless cards and drivers if it involves no risks?
Removing the plist is not going to solve the issue.  The 3 wire versus the 2 wire are for the WiFi and Bluetooth antennas, and have no bearing on whether or not your Mac sees the hardware.

If you go into System Information (About this Mac > System Report) then scroll down to WiFi, it should give you information about the WiFi adapter.  If it doesn't, it's not being detected and no amount of jiggering with plist files will fix it.  It's time to look at either the new WiFi card is defective/incompatible or the mPCI slot on the logic board is faulty.

Given that you are attempting to fix a 2008 MacBook Pro, I wouldn't spend too much time trying to repair a WiFi adapter or deal with a potentially bad mPCI slot..  Instead, get a USB WiFi adapter like the DLink DWA-171 which supports 802.11ac and is fully Mac compatible (I'm using it on a 2009 MacBook Pro as I type this).