I think the G5 cast will be middle school aged, or _*maybe_* first half of high school (if they were humans). Hitch is probably older than most of them and has a job (explaining his badge). Or, he's closer to their ages (maybe older high school) and is a junior sheriff-in-training.
I'm leaning towards Hitch being Sunny's older brother and having a role and personality similar to Sokka from ATLA.