I got it working. After I used my Game Stop Early Access Code to redeem through Square Enix, I pressed the "Alternately, redeem your code here." WHEN I WAS GIVEN THE CODE FROM SQUARE ENIX. THE SAME CODE THEY GIVE IN THE E-MAIL. ON THE SCREEN AFTER I SUBMITTED MY GAMESTOP EARLY ACCESS CODE.

I clicked redeem code, entered the code they gave me, and at the same time I registered for my CE items.

Don't know why all of this is so fussy.