Nor are they part of what the characters are.
Ah, but to what extend does our external stimuli become a part of what we are?
If I told you my grand mother was a hoarder, you might say "ok".
If I told you she lived through the Great Depression, you might say "ah-ha!"
In my current WIP it's "peacetime" so I'm painting the local characters as "trusting". Except Nova. She's plotting and distrusting. Why is she distrusting... because the (local authority) is out to stick it to her. I've allowed this external factor to colour her.
That's kinda what I missed in yours a sort of "X is on path Y because of factor Z"
For instance, what is it about Lortimer that would make him want to invite the other student for dinner, evidently for the sole reason that he's serous? (Maybe he was shown kindness once and now tries to deliver it back? if so, how does this drive his soul?)
You touched on P's family-member's death, but now how that has affected her? If not at all, that's just as telling as if she's developed a tendency to check in on people to their distraction / annoyance).
I wasn't looking for meaning attacked to every character tick, tho. Was just observing that I didn't spot any