Fox has two sons that aren't given names and are only visually differentiated by the color of their overalls. This role is for the son that wears yellow overalls. He appears to be the more competent and "go-getter" of the two. While he does help his father out in his evil schemes, he's still every much an innocent child that is simply doing what his dad told him to do.

Use Miles "Tails" Prower from the Sonic franchise as a vocal reference but I am open to other interpretations.

Miles "Tails" Prower - https://www.youtube.com/watch?v=Y6b3JoDW0lM