Character mistake: Freddie mentions that they had an audience of 355k which was the most they've ever got. But in the earlier episode of ISpy a Mean Teacher, they had an audience of over 500k.
Continuity mistake: When Carly's cousins come over, Sam goes upstairs to read a book. When her cousins are gone and Carly goes upstairs, she sees a boy rubbing Sam's feet. In between shots, Sam's right foot goes from facing inwards to being flat.
Other mistake: When Carly and Sam are pumping the watermelon full of air, one shot zooms in on Carly's finger as she hits the on-switch. The device is turned off as she removes her finger. (00:01:32)
Continuity mistake: When Carly and Sam are on the web show at the beginning, Sam puts the air hose around the edge of the watermelon. When the camera cuts back to the watermelon later on, the air hose is in the center of the watermelon.
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.