Claire's parents. It's been mentioned that her dad's a college professor and not currently unemployed - why do they continue to be so financially dependent on relatives, staying in their guest house and letting Massie's folks pay their kids' private school tuition. Surely at least renting a place in a decent school district, getting Claire into a charter school affiliated with dad's university, even looking at Catholic school would all be options on the table. Given the effect Massie, the PC and OCD is having on their daughter, even an Inner City School would be preferable...
Why don't Kristen's parents do the same thing? Why don't Dylan's parents (or parent) wise up to her eating disorders? MST3K Mantra indeed...
Massie's "allergy" to nuts. In the first book, Massie can't try out their homemade lip gloss because peanut oil is one of the ingredients. A few books later, she's shown to be eating Nutz Over Chocolate Luna bars. Fair enough, the author could have simply forgotten about the allergy. But in The Clique Summer Collection: Claire, Massie claims, once again, that she's allergic to nuts, which Claire—silently—figures is a bluff. Except... is Massie allergic to nuts or not? Was she lying in the first book (even though there was nothing to suggest she was), is she lying in Claire's book, did the author totally forget about the allergy, or is she deliberately retconning it?
Claire later mentally mentions a "shellfish" allergy that Massie claims to have, but only gets mentioned when Massie doesn't want to eat something. Maybe she didn't want to try the lip gloss because she thought it was beneath her (her endless disgust for low-cost or non-brand options), but didn't want to actually SAY so.
Are breast implants for middle school aged girls even legal?
With parental permission, there's probably a surgeon corrupt enough to take the money and do it.
There are also plenty of back-alley and out-of-country surgeons who won;t ask questions.