Well, Jooce, with the one you created and I forked a bit, in my version, Jasmine is out for revenge, but is not as vindictive as you might think.
In order to 'harm' Sarah, she has to 'harm' herself. Because she can't directly do anything to Sarah.
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She declares herself Head Cheerleader...Sarah's job. Sarah therefore can't be head cheerleader.
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She declares herself the most popular girl in school...You can have two popular girls, but only one can be MOST popular.
Both of these things are a core part of how Sarah defines her identity. So, if Sarah isn't the Head Cheerleader, and isn't the most popular girl in school...she must be something else.
The problem is, to do that, Jasmine has to become those things. But nothing says she has to be self-centered the way Sarah tends to be cast. She could have the cheerleaders out having a bake sale to raise money for the homeless or something.
Meanwhile, Sarah has to deal with the new her. That doesn't necessarily mean she ends up in a bad position, although it could be. Just a different one. Maybe that is growth for the character and redemption, which is a classic theme.
Elsewhere,by the way, in the Jordan branch, I had planned on trying to write up a 'reason' why you would recruit cheerleaders from the male student body. Aren't there enough females at that school? Thought there might be an interesting angle there that might explain the motivations of the 'Cheer Coven'.