Other mistake: At the beginning, when everyone is watching Shelby fighting on TV, the timer is going too slow. According to the timer, the fight ends at 2:53, which is only 7 seconds of fighting, yet the fight was way longer than that.
Continuity mistake: In the beginning, Carly gets a bowl and fills it with popcorn up to about 2/3 full. The camera cuts to Sam, then back to Carly, and the bowl is barely full. The camera goes back to Sam then to Carly again, and the bowl is 2/3 full again. Freddie walks in, and the bowl is barely full again, which Carly now fills with popcorn.
Revealing mistake: Carly, Sam and Shelby all corner Nevel in the ring. If you look in the corner where Shelby shows up, she's not in that corner until the light flashes on her.
Continuity mistake: When the gang is at their apartment watching the news over how they think Carly pushed Shelby's grandmother down, there is a ladder outside their door that appears and disappears from shot to shot.
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.