Continuity mistake: When Sam bangs on the locker with the hammer, the amount of damage on the metal repeatedly changes; it decreases, increases, decreases, and so on.
Revealing mistake: When Carly's in her dream and attempts to use the elevator, if you look really closely, she doesn't actually hit the button that lights up.
Chosen answer: I don't know how to answer the first question but for your second question, there is going to be an episode after iPWV, called IDate Sam & Freddie which will deal with their kiss from iOMG. IParty with Victorious will not be related to IDate Sam & Freddie.
The I date Sam and Freddie proves that they are a couple.