While Freddie and Sam are talking to Superintendent Gorman after learning that Principal Franklin has been fired, a black girl in a blue top can be seen coming down the stairs in the background twice.
The first time Spencer rides the bull in the apartment there are stabilizer bars attached to three corners of the base, but not the front left-hand corner. The second time he rides it, with pillows strapped to him, there are now stabilizer bars attached to all four corners of the base. When Bucky arrives, the stabilizer bars are gone from the front left-hand corner again. When Superintendent Gorman rides it at school it has the bars attached to all four corners again.
While Principal Franklin is in the iCarly studio there is light shining in through the windows indicating that it is light outside, while at the same time, when Spencer is riding the bull downstairs, it is dark outside.
Before Sam punches Freddie, her bag is on her left shoulder, in the next take, when she punches Freddie her bag is over her right shoulder and almost flies off with the punch.
When Superintendent Gorman is talking to Principal Franklin about getting his job back, one time it shows Carly, Sam, and Freddie all holding hands and looking excited but a moment after it shows them all standing apart looking confused again.
The superintendent should have not have the authority to fire Principal Franklin for being on iCarly. Principal Franklin made an appearance on the webshow on iGot Detention. Miss Briggs made an appearance on the show too playing the bagpipes on iSpy a Mean Teacher and she didn't get fired for that.
Superintendent Gorman can't just appoint Mr. Howard and Ms. Briggs as Ridgeway's new co-principals. In order to be a principal at any school, a teacher must obtain their Masters Degree in Education Administration, plus have long time career in teaching. Therefore, what Gorman did would not be allowed in the first place.
Principal's don't typically have the authority to impose school uniforms.