6'4 minimum bro is built like Slenderman and moves like Jack Skellington.
Either mockingly or affectionately gets called gramps or peepaw by the rest of the rogues even though he's not that much older then them.
SOUTHERN BOI, the most common headcannons I see around for Jon in this category are he's from Georgia, he grew up on a farm, and he makes great comfort food, and I subscribe to all of these but it's missing that special southern pizazz, that being SILLY SOUTHERN EUPHEMISMS AND PHRASES! I can see him trying to cover them up most of the time cuz he wants to be taken seriously, but sometimes they slip out anyway and it always confuses the shit out of rest of the rogues; He pretty much becomes indecipherable when he's REALLY happy or drunk, cuz then the filter comes off.
Can't drive for shit but can ride a horse really well... don't ask me how that works, usually uses public transport. Has both a really banged up rusty pickup truck, and a rather big horse named Equinophobia.
Either bisexual or aroace and not a soul in-between in my book, also BOTTOM.
Cares a lot about people learning and tries to encourage it most of the time. Despite him coming off as a little creepy sometimes, I still see his students actually liking and respecting him quite a bit, and to me he seems like the kind of teacher that's strict but fair, REALLY old fashioned, and is willing to work with any students that are close to/ failing one on one.
If the school is having a Halloween based event Jon finally comes out of his little hidey hole and actually volunteers. Hates any professors that brag about how hard it is to pass their class, cuz Jon doesn't see the class being hard he sees the teacher being bad at their job.
7. Has befriended the local crow population and has named them after phobias of course, he gives them food or little things they might want and they in turn give him little shinies or let him pet them. Sometimes the crows will switch up and peck or swoop him if he either does something they don't like or just to be little shits.
8. Lives in a run down little shack on the edge of a small town with Gotham being visible in the distance; Treated like an urban legend there. Obviously Jon has multiple hideouts, but this his main one.
9. Rather good with crafts especially ones involving cloth for obvious reasons.
10. Jon and Harleen are rather popular around Arkham asylum given the fact that they know the place pretty well and have personally worked with both the staff and the inmates. Arkham might as well be a second home to the two of them in a weird twisted way, they're also besties cuz yes.