Some of my Who cadet designs! Two are OCs, while two are technically repurposed Seuss characters even though one of them started out as an OC.
The tall boy with wavy black hair and lime green eyes is Sergeant Kristoff Fairfax (age 16). Unlike most of the other cadets, he actually volunteered to join the academy, mostly to prove to his parents that he truly was mature so they'd stop calling him a "lazy freeloader". Before Schmitz's redemption, Schmitz made Kristoff serve as his "right-hand man" whenever he could. Nowadays, Schmitz is a lot more laid-back with how he treats Kristoff- but that doesn't mean Kristoff doesn't still like to assist Schmitz at times.
The medium-height boy with long auburn hair and brown eyes is Corporal Caelen Clark (age 11). Before Schmitz's redemption, Caelen was often bullied by some of the other male cadets for seeming too "girly", and he absolutely hated that. He's actually named after my supervisor at work, who's a really nice man- and Caelen himself is just as friendly.
The short boy with light tan hair and blue eyes is Private Jayson "Jay" Umbroso (age 9), and the girl about his same height with light orange hair in a ponytail and blue eyes is Private Kayla "Kay" Umbroso (age 8). Before you ask- yes, they are indeed the Seussical incarnations of Jay and Kay from One Fish Two Fish Red Fish Blue Fish. (Jay started out as an OC with darker brown hair and named after someone else I worked with, but I eventually got the idea to remodel him into a version of Jay from One Fish Two Fish.) The two of them (or just Jay in versions where the academy is boys-only) were sent to the academy because of their pet obsessions, around the time they brought the creature they called "Clark" home from the park in the dark. In versions where JoJo is male, Jay is his bunkmate, and in versions where JoJo is female, Kay is her bunkmate. Schmitz originally insisted on calling the Umbroso siblings by their full first names, but it was hard for the cadets to tell if he was saying "Kayla" or "Caelen" sometimes (such as when it was noisy or he was far away), so eventually he started calling Kay by her nickname, and Jay thought it only fair he get the same treatment as well.