Hello,
yesterday I had the exact same issue (parking lights and turn signals swapped) after installing Valenti taillights on my French GT86
Thanks to your records, I could fix it by swapping the blue and
yellow (not white on Valenti lights) wires.
As not everybody faces this problem, I guess FRS/GT86/BRZ are not all wired the same way.
What is weird is that manufacturers do not seem to sell several versions, depending on the target country.
Anyway, thanks for your help !