@TreyNutz You know what? I didn't even think about the possibility that buying my sims' children bicycles and designating which child each belonged to might eliminate the school bus the way designating preferred vehicles for adults eliminates the carpool. Maybe that's the issue this time, though it wasn't when my sim was a child, as I never actually bought her a bike.
I didn't ever actually unpause the game after I changed the children's school performance. You're probably right, it would have changed once the game started moving again. I thought the performance bar had to be full for a few days before the grade became an A. But I guess that's for the honor roll, not the grade. So maybe it wouldn't be so bad to just go ahead and replace the rabbithole. Her dad already got the points for his wish to see her get on the honor roll. Maybe he'll wish it again and get more. LOL! But if it's the bicycles that are causing the school bus issue, then I guess I'll have little choice but to live with it. I'm not going to take away their bikes. They were birthday presents, each bike in its owners' favorite color. You can't get that with the default vanishing bicycles.
@igazor Doesn't resetting the whole town do the same thing to everything as resetting one object does to that one? I reset everything every sim week, right after Overwatch does its 3 AM maintenance on Sunday mornings. The town has been through at least 2 resets since the school bus quit coming. That's why I decided to try replacing the rabbithole instead of resetting the school. I can try it and see if it works. It would certainly be less disruptive than replacing the rabbithole. But maybe it's just the bicycles. Maybe I need to just live with it.