Thanks Ross & Ian,
I think I have it figured out. Ian, you found the same thing I did, orphaned files. So what I'm doing is collecting the orphan files for each of the teachers who were part of that grade level team over the past few years, putting those all into a single location, and then the current teachers will just have to sort through it all.
I've been building a plan to move the entire school to Shared Drives and this will be just another reason to convince everyone that we need to do this soon. I'm just happy those files were still recoverable and that only the oldest files would've been deleted. The deleted teacher hasn't worked here in maybe 10 years. I'm also working on building better policies for suspending and deleting accounts (been the IT manager here just one year so far).