dealing with crisis

If your school/district has an EAP, staff can always access that. It might also be worth it to look into having a dedicated grief counselor for staff (I know the crisis team may have one or several, but grief isn't usually succinct).

Perhaps some staff who weren't super close with the individual would be willing to organize a celebration of life at the person's favorite restaurant or a potluck after school just for staff to attend? Perhaps the PTO would be able to pitch in for some food or utensils? 

And don't forget to care for yourself! While others saw what was happening, you were deeply involved. I hope some of the staff have checked in with you. I have not gone through anything remotely like that, but I feel like the staff all forget that we aren't stone-cold about medical events and they can rattle us just as much if not more, especially if we had to act. This was super apparent at the height of COVID - the teachers were all so worried about each other, they completely forgot to see how I or the other nurses were doing...

I agree with the need for staff to get the support they need to process this. I have nothing to add to what's already been suggested.

I think it's also important to address the "several classes of elementary students" as well as the parents who will have to deal with the fallout. Presumably, the crisis team has some ideas  for the students as well as their parents. This might include access to individual counseling for students, an in-house memorial, group education/support sessions, scheduled for times parents can come.

I have learned that grief takes the time that it takes. There are no rules about how to go through it, just more or less healthy ones. Cut yourself and each other some slack.

First, I am so sorry for your loss and kudos to you for knowing you did all you could.

There definitely needs to be a debriefing for all involved directly. Check with your local EMS to see if they have access to a behavioral response team. Then see if you can, connect with them, There are trained professionals who will come in and do this. I found it immensely helpful when invited to the FD/PD meeting after the MVA of a student where I was the 2nd on scene. Our police chief had the foresight to invite me and I will be forever grateful.

As  k1pssk stated be sure to care for yourself, as many will lean on you for support.

Big hugs