The pentalobe screws refused to come out
I had read somewhere that Apple may use Loctite to insert the screws. I researched on the Internet how to loosen up Loctite. The answer was to use HEAT. I heated up the screws, using my glue gun nozzle (without the glue, of course) and when the screw was hot, using the Fixit screwdrivers, the pentalobe screws came right out.
Yes, heat up pentalobe screws before you try to remove them and strip out your screw heads and screw drivers.