Thanks for your input! The two Light Purples are indeed quite apart in hue. I don't think either is Magenta, I have a Magenta part in this pic and it is a different from both these Light Purple variations. For the time being, I will consider these both Light Purple. I am considering picking the parts from my stock to "build" a 4679b-2 set. (t looks like I have parts for two copies, almost complete.
The Bright Light Blue bricks are different not only in color, but some other small detail. The stud logos are quite different on the two bricks. Then again, this can be a manufacturing inconsistency. On the left brick, there is a "ring" around the logo, and the letters are not so "sharp" and they are less tall. On the right one, there is no ring, the letters have more definition and they are slightly taller.
The color of each bick is perfectly even, too even to be yellowed. Same color on every surface, even on the insides.
Again, I will consider these two to be the same color, for the time being. The difference is very subtle. If in fact I have two copies of the set these came with, this is the most likely explanation why I have these pieces in the first place.