When talking about being the Gunnerson's, Monica twice pulls the top half off the French bread to butter it.
The gang goes to the airport to send Marcel to San Diego. They are with him at the gate and he gets in the cage. A monkey would not be traveling in the cabin, they would have had to drop him off at cargo.
Fake Monica says that the guy at the end of Dead Poets Society kills himself because he can't be in the play. This is wrong. He kills himself because his father has completely planned out his life, and he has no choices about anything. He feels totally trapped.
Rachel's signature wristwatch comes and goes, disappearing fully throughout the remainder.
Fake Monica tells the real Monica they are going to audition for Cats by singing "Memories". Cats has the song "Memory", not "Memories". Later on when fake Monica is in jail, the real Monica makes the same goof.
When Monica meets Fake Monica, she says her name is Monalla and that is Dutch. When Fake Monica starts speaking Dutch to her, she corrects it to "Pennsylvania Dutch." The Pennsylvania Dutch aren't actually Dutch, it's a misnomer; they're German.