well I was thinking more from a narrative/characterization purpose.
What narrative purpose do you want to give the arc? For example you could make the arc about de-weaponizing/helping Anna be more 'normal' while in the larger context of the 'anime' Anna and Shuri can provide a warning to Coke Zero on what could/will happen if he goes too far (or making the point that there are no heros, only soldiers... tired tired soldiers).
I do agree that Anna's PTSD is probably her most character defining aspect that would have her stand out compared to everyone else. The thing is, we've already played that card at least twice.
The first time was when we sparred against Koujirou and then freaked out that he hurt himself. His response was to just say 'it would be fine' when we expressed our concerns towards him and then drop it. Setsuna wasn't much, if at all better, and while Yukari has shown a general awareness that Anna has problems, she seems to have mostly chalked that up to a side effect of us being in Anchorage.
The second time was when we did the Single Sweep scenario, at which point Sandra and Shuri
did notice, and it started Sandra's interest and attempts to help Anna deal with her issues. Shuri has been seen willing to help Sandra out with this when asked or she feels Sandra is making a mistake, but otherwise taking no overt actions. Koujirou, Setsuna, and Yukari, however, didn't seem to notice at all. Yukari seems to have had an excuse though.
So if we do want to trigger that arc, it has to be triggering it with Sandra and hopefully Shuri. I suppose after typing this out, I have come to the conclusion that it could work if we can push the current interactions with Anna and Sandra into it's own arc of 'help Anna!'. I'd personally like to include Shuri too, and in order to get screen time we need to get Koujirou to be aware of it. I don't think Koujirou is going to genuinely notice outside of either stealing the limelight from another character that could handle the situation better (someone who would actually deal with the issue instead of aggressively sweeping it under the rug) or until Anna has a full mental breakdown. I am a fan of neither.
If we were to extrapolate this and find a way to safely include the entire class, and by extension Koujirou who would proceed to be aware of the situation but not actively participating it, that would be ideal. Any idea on how to start this?
We do other stuff with them, like get them up on Impeller skill to begin teaching them fun tricks. And maybe poking around Koji's frame to try and induce more weapons, while Setsuna tsun's in the background.
While plans to get Anna to teach will hopefully pan out, she currently is horrible at it and while this would make things up to others, it wouldn't help much in the reduction of Anna's character relevance. She'd get some screen time, but not enough to make up for sitting out yet another tournament. I'd prefer to keep the path of making Anna an interesting character for the audience as viable as possible while pursuing other paths, so that doesn't really deal with my issue.