In followup to my previous post, I launched TechTool Pro 9.6.1 and ran the Sensors Test. All Sensors tests were passed. These included:

LCD Proximity, LCD Thermal Compensation 2, LCD Proximity, Thermal Compensation. Machine seems to be running fine.

This was connector was impossible to remove. Like a previous commenter, I did this with the machine upright and with the LCD Panel resting on my upper chest. Ultimately, the pins pulled out of the socket! Once they were out, it was relatively easy to remove the socket. I completed the drive replacement, (installed a 1 TB SSD) and then replaced the pins in the socket and reassembled the machine. One mental error I made was I couldn’t remember the correct orientation for the Black and White wires in the socket. In looking at the photos here on iFixIt, it looks like I reversed their orientation. However, the machine seems to be running fine. I installed macos High Sierra and migrated my data from my old HD and the machine has been running for two days now. I would hate to have to go back in and remove the socket and reverse the wire orientation. Anyone have advise on this?

I used a 0.8 mm (1/32") drill bit to tap the screw hole. ==> Dremel 628 Precision Drill Set (available at Home Depot). You only need a minimal "starter hole" as the screw is self-tapping.

On my replacement Rear Panel, there was no screw hole for the Phillips #00 screw used to secure the 'black plastic spacer'. The screw appears to be a self tapping screw. I would suggest 'tapping' the screw hole first before installing the antenna housing.