Just some Things(tm) that occurred to me, knowing that Grace taught in Middle School (as someone who works with middle schoolers):
The students ABSOLUTELY gave him a nickname. If you are a well-liked teacher in a middle school, the students are giving you a dumb fucking nickname (I would come up with some examples, but the nicknames are 1. Never logical and 2. Almost never that related to your actual name. So I could say they called him Professor Tuna and yall would just have to believe me on this one)
Additionally: if PHM takes place in the semi-present, a student DEFINITELY made one of those pink flags with Grace's face on it.
I am absolutely sure Grace would be the kind of teacher who had classroom memes--ones that only the students in his class would know, and would confuse the other teachers in the building and annoy the students who hadn't had him in class yet
Have you seen those tiktoks where teachers share how they ragebait their students with their lame jokes? That's Dr. Ryland Grace to a T
However I can also see Grace being the kind of teacher who demands to be in on the gossip whenever he overhears it, and gives the kids sappy advice to get them to make up with their friends
As a young, single, childless teacher, he definitely got volun-told to chaperone all of the dances and events throughout the year. I am sure he would come dressed in something (appropriate, gotta keep that job) but also a little silly to make the kids cringe on purpose
He probably had a line form at the end of every school year of students waiting to have him sign their yearbook. It probably only ever became a line because he would write a personalized message to each kid.
Grace was probably the kind of teacher who made sitting through staff meetings bearable OR the one who always made the staff meetings go over time with all of his questions
I fully believe Grace did a Transition to Teaching program after being laughed out of academia for his dissertation, so I can just imagine him as a first year teacher being like "....a 5-0-what? What is a TOR?" (cut to frantically making flash cards to keep track of all the new terms)
Just cuz I want to make myself sad: I bet, after being out in space for a while and getting some of his memories back, Grace remembers his last group of 8th graders, and realizing how much time has passed, makes himself cry thinking about the fact that they have probably graduated high school by now. He can't help but wonder what colleges they are applying to, and if they still have the same dreams for the future that they did when he knew them. He wonders if he can save the earth in time for them to see those futures.