Hmmm....I’m not sure what the Rules were...and I don’t really know why....but nobody wore costumes at my Grade School, in North Carolina, back in the 60s. I think it was just understood that costumes were for later that night.
Of course, the school celebrated in other ways....and they had no problem with calling it Halloween.
Yep. That was my experience in the North, too. A separate, evening Halloween party, but some in-school Halloween decorations and references—just as there were for the other holidays celebrated by the majority of, or all, students.
Yes, my experience was pretty much the same here in my area of NC, also in the 60s. We didn’t go in costume to school but we got to draw black cats, witches, color construction paper pumpkins and jack o’lanterns, and one of my teachers even let us make up and write our own Halloween stories that we then got to read in front of the class (3rd grade). Not one person, that I’m aware of, ever got hysterical about it being called Halloween. We just did it, had a great time, and the next day it was all over and we were all looking forward with excitement to Thanksgiving. It was a great time to be a kid.