In this case the daughter still has only a 50% chance of being colour defective. Blue colour blindness is far less common, being present in just 5% of all colour blindness sufferers. The genes affected are equal in both sexes.
The cheapest days to fly are usually Tuesday, Wednesday and Saturday. While your information may be only anecdotal evidence, it probably confirms what FareCompare.com's careful study of airline supply and demand confirmed in a 2011 study of U.S. carriers.
If you can be flexible on when you fly, you can also save money. Whenever possible, purchase your tickets for Wednesday, Tuesday or Saturday, in that order. Friday and Sunday are the most expensive days to fly.