Visible crew/equipment: After the theme song ends it starts with Lois just finishing shaving Hal's back. Off to the side you can see the crew kneeling down.
Continuity mistake: While Dewey stands on the table, Mrs. White (Bea Arthur) dips her finger in the bowl of chocolate and draws a mustache with it on Dewey. In the following shots the chocolate on Dewey's face differs.
Continuity mistake: When Malcolm and Reese talk about April at the water park, there's a girl with a blue shirt and a towel tied around the pelvis who passes behind Malcolm twice in two different shots.
Visible crew/equipment: You can see the crew right after the intro. (00:01:00)
Answer: It is made up - although it is implied she is Croatian, she never mentions it herself.