What is Khan Noonien Singh? He's NOT a Sikh, since Sikhs are forbidden from removing or trimming any hair from any part of their body. Khan was clean shaven and waxed his chest.
What was Khan's skin colour? He has makeup darkening his skin in "Space Seed" which he doesn't in Wrath of Khan, where he looks white.
His followers completely changed to all white/blond in WoK and were suddenly much younger.
Like it or not, Khan's backstory and racial identity was a jumbled broken mess long before Into Darkness.