I eventually got the movie, but only by guessing ones that started with the first antonym. After 10 minutes of googling, I'm no wiser. Dang you kalbahamut, this is going to bug me...
It shouldn't take too much longer than 10 minutes of googling to figure it out. It's pretty obscure, but with the Internet the answer is there. I just used google to find it myself...
I already ate them all anyway so I'll just tell you. Sonia is a Russian variation of the Greek name Sophia. It means wisdom. Nabal is a Biblical name. It means "fool, senseless." Red is the complimentary color (opposite) of green. Thus the opposite of Red Sonja = Green Nabal.
Also, shouldn't Guess Who's Coming to Dinner be Tell Me Who Isn't Going to Breakfast?