Continuity mistake: When Tom is proposing a toast to Lynette in the bar, he's holding the coffee with his left hand. However, in the next shot he's drinking the coffee with his right hand, and when the shot changes he's holding the coffee in his left again.
Continuity mistake: When the boy paints "witch" on Mrs. McCluskey's front door, he holds the container in his left hand and the brush in his right. But when Karen gets out and he runs away with the other kids, the two items switch positions.
Continuity mistake: When Julie is tutoring Austin, he takes out a beer can, drinks it, crushes it and puts it down on the desk. A couple of shots later when Julie stands up, the beer can has rotated itself slightly without Austin touching it.
Visible crew/equipment: When Edie is talking to Julie and Austin about their sex life, the pole of a boom mic can be seen reflected in the window behind Edie.
Continuity mistake: During the dinner scene at the Van der Kamp's home, Danielle throws her plate against a wall, but when they pan back to her, the plate is still on the dinner table.
Like It Was - S3-E4
Continuity mistake: When we see a close up of Orson making a cup of Cappuccino, you can see the cup is filled with steamed-milk foam, but as the scene changes there is less foam in the cup than there was in the previous shot.
Visible crew/equipment: When Carlos is speaking to Charles (Travers' father) outside about joint custody and Charles says "Y'know, I just don't get it", a boom mic and pole are reflected in one of the windows near the front door of the house.
Visible crew/equipment: When Ed opens his car door for Lynette, the camera crew are reflected in the side of his car.
Answer: Kayla was sent away in episode 16 (The Gun Song) in season 4, after falsely accusing Lynette of child abuse. She now lives with her grandparents - probably Nora's parents.
I'm curious why we never see her again, why she never talked about, and why Tom never mentions visiting her.