The big plot holes I mentioned are actually unrelated to that. More specifically, the conundrum of "why does nobody fucking know each other?"
There are two specific instances:
1) Black Star's backstory establishes that he grew up at the DWMA. That implies that he would have probably really gotten to know the staff there, including Lord Death himself. So why doesn't he recognize Death The Kid? You'd think they would have at least met before this. Kid seems to know his dad pretty well, and he literally never leaves the academy. And Kid's not the only one he doesn't know...
2) Nobody recognizes Stein.
Imagine if, when you were a kid, you wanted nothing more than to be a musician. Your mother and father were musicians. They studied at a prestigious school of music; the same one you attend full-time, with all of your friends who also want to be musicians.
Now imagine that neither you nor any of your friends know who Beethoven is.
And that Beethoven went to your school.
And also that your dad was close colleagues with Beethoven for seven years.
Considering that Stein is apparently this world-famous genius meister, it's just plain odd that none of the kids have any idea who he is when they first meet him.