Other mistake: In this episode, Felice and Dr. Martin are supposedly celebrating their 25th wedding anniversary. In the sixth season episode "Earthquake Weather, " Felice told Donna that she had to drop out of the Rose Court competition after getting pregnant. She got married at that time, and suffered a miscarriage. In the earlier episode "Offensive Interference, " Donna saw her mother in a photo of the 1969 Rose Court contestants. Therefore, Felice and John should be celebrating their 29th anniversary, not 25th.
Plot hole: Noah cancels the club's scheduled Monica concert because Dylan pays him to have her give a private performance to Dylan and Gina instead. He seems really excited and proud of himself for some reason. Even if Dylan paid him much more than he would have received from the gate (which is likely), this could cost Noah money in the long run. Many customers would probably get angry and decide to stop frequenting a place that would cancel a concert at the last minute for no good reason. Then again, Noah was never exactly a genius - in business or otherwise.