Very low chance. While there are no statistics, the chance of a person's two eyes being different colors (heterochromia) is extremely low. More commonly, some people are born with a segment of one iris being a different color from the rest. Also, certain diseases can either increase the brown color (nevus, melanoma) while others can lighten the eye (certain inflammations and glaucomas).
Don't think it known. I researched this and don't have an answer on the odds. It is described and described as genetic. Probably rare enough that odds aren't known. Let's see if this plays out by going to our ophthalmology colleagues on healt tap? Sorry, i 'm not seeing blue nor technicolor!
Very rare. In humans it is considered a rare occurrence. It is estimated at 0.006% odds. Or roughly 6 in 1000 people. That makes it roughly around 250, 000 people in usa. Read more...