Question about character designs

Hello Mr. Korman! I noticed in previous posts that you would give some insights on how characters are supposed to look, which made me curious about what you imagined characters to look like when writing your books, because usually their appearances are given minimal descriptions.

Specifically I was interested in your interpretation for the main characters of some of your books, particularly Chase (Restart), Yash (Slugfest), Donovan (Ungifted), Cooper (WhatsHisFace), and Jett (Unplugged)