Fiona

Fiona Jane McQueen (or simply referred to as Fiona) is a fictional character in Kevin gets Grounded. She is Kevin's sister and the daughter of Sally and Lighting McQueen.

Creation
Fiona was created after season 2 because Brooks wanted a sibling for Kevin so he could get into more trouble

Re-coloring
Fiona was originally going to look like Sally. but Brooks said that there was some "confusion" between Sally and Fiona. So then he "re-colored" Fiona into a purple color.