Many people often wonder why Kimberly Drummond never appeared in more than the open episode despite being an Eastland student. There are many theories about why and here is mine.

I think Charlotte Rae didn't want any negative influences around her girls on the set. At that time Dana Plato was already getting into substance abuse. Kim Fields, in her book, describes Dana Plato being spacey and showing up dressed weird with oddly colored hair. Plus Gary Coleman was a brat and tyrant on the set.

I used to think the writers never bothered to write for her on FOL, but I never thought about Charlotte's clout. If indeed that was a factor, which, who knows? Your theory is plausible.

I also believe your theory is plausible.

However, I have always believed it was because NBC executives were already claiming, by the fourth episode, that there were "too many girls" at a girls' school. So Kimberly got expelled from her own school, and Nancy became wallpaper. By the end of the season, they were chopping girls out of scenes left and right. And by the start of the second season, there were only four girls left in a school where we'd previously seen 23 girls. "Where'd everybody go?" Mindy said. Where indeed, Mindy. Where indeed.

You'd think they'd make an exception though with crossing over a guest star from their parent show who would be a natural fit, in order to help boost ratings and stimulate stories.

Again, you'd think.