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.
IMeet Fred - S2-E10
Character mistake: Carly says Shelby, ID Is 4 hrs away. It's more like 11 and a half hours from Seattle.
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.
IStage an Intervention - S2-E2
Visible crew/equipment: When Carly and Freddie are talking in the hallway about his bad luck, you can see a crewmember's shadow on the wall next to Freddie.
IStage an Intervention - S2-E2
Visible crew/equipment: Every time the shot shows the chair between living room and kitchen (when they show where the chair is), the reflection of the studio light is seen on the bottom of the chair. For example here when Carly looks at Pack Rat, when she walks, you can see the studio lights at the bottom of the chair.
Revealing mistake: During the shot where Chuck flips Spencer for a brief second you can see his face, which reveals that it's a stuntman as he is a different person.
Continuity mistake: Spencer is talking to the Sunshine girls about stealing his spot. After he gets pushed in the street, when his skateboard goes flying and breaks in two, one half goes offscreen, and one goes under the table. In the next shot both halves are by his feet, but in the next shot they are back in their original positions.
Continuity mistake: When Spencer and Carly are blowing bubbles to the ceiling, when the bubbles pop, and the soap comes down, Carly's hair is all knotted and messed up. But when she sits up, her hair is perfectly parted and straight.
Continuity mistake: When Lewbert is on the ground and everyone's in the lobby, you can see that Carly's shoe doesn't have a large wart before Lewbert screams, "Where's my wart!"
Continuity mistake: There is a scene where the iCarly gang are arguing with Nevel. Sam went to beat Nevel up, which during the process made her hair messy and her headband slipped backwards. However, in the next shot her hair is not messy and her headband is perfectly normal. This keeps happening several times throughout the scene.
Visible crew/equipment: When Spencer is replacing Lewbert, you can see the studio lights reflecting off the bronze dome.
Continuity mistake: Sam fights Freddie about a bikini. When he wins he throws it down. After the fight, there is a close up of him. You can see a flag in the window of the door. Then two girls walk up. In the next close up, the flag is not there.
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.
Continuity mistake: When Spencer first gets his Galaxy Wars thing, it doesn't show the sticker that says it is not a real prop from Galaxy Wars until Freddie tells Spencer.
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.