By the 1996 setting of the film, only the lowest budget TV dinners had aluminum foil covering the meal. Plastic wrap had replaced it and even the food trays themselves were mostly hi-temp cardboard or corrugated paper.
When Buddy and Miss Purdy go to Scream for the first time, it appears that their table is almost directly opposite the front of the stage. When Buddy later plays the piano on stage and sings to Miss Purdy, he is facing to the left of stage (ie. not in her direction). If he wanted to face her while playing the piano, his head should be turned to his right rather than looking straight ahead.
Klump returns home after getting a date with Carla and puts a frozen dinner in the microwave. The frozen dinner has an aluminum foil cover that Klump does not remove, but there is no evidence of the sparks that would result.