These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Alternate Character Interpretation: Did Rhonda think Macey and her friends were still pulling a joke on her, or did she know that the ghosts of the dead school bus kids were real and just left them to die?
Alternatively, did she remember Macey saying that the elevator would only hold three people safely, and thus assume that they'd throw her out and leave her to die?
Another possibility: the other children had already presented themselves to Rhonda as being dead. It's possible she simply believed them...
Yet another possibility (wow she's a fun character): she seems to be the only person in the movie who Sam actually likes (the best anyone else gets is indifference), likely because they both believe obsessively in the rules of Halloween...they broke the rules, she couldn't interfere with the punishment...
In Seasons Greetings, the short that marked Sam's debut, was the man who tried to beat him to death a reprehensible thug who didn't know what he was getting into, or someone who knew what Sam was and tried to get rid of him before he caused any trouble?
Did the School Bus Kids kill the other children to help Rhonda? Alternatively, however, jack o'laterns seem to have a protective power in this universe, so its possible that once they were smashed, the kids just unleashed there rage on whoever happened to be there..