I think a lavender or periwinkle could be easily substituted for the gray -- but I sort of used up most of my purples as year or so ago. One of my early single fabric only options was a slightly slate toned medium blue but it turned out I didn't have enough yardage, it looked really nice with most of the other colors too.
I have problems with the Parakeet... I'll probably be shifting to more aqua or just a different green.