Visible crew/equipment: When Jazz says "oops!" the stage lights are reflected in his glasses.
Continuity mistake: When Hilary starts crying, Tyrone is wearing an apron. In the following shot he is suddenly not wearing it, but in the next shot it is back on. (00:12:55)
Other mistake: When Will confronts his mother about not wanting to move back to Philadelphia, she mentions she can't afford to send him to an out of state school. However, in season 2 it's already been established that Uncle Phil is Will's legal guardian, and he's a resident of California. Will's mother has it backwards. Going to school in Pennsylvania would be an out of state school and staying in California would be in state.
Continuity mistake: Will's hat from his school uniform keeps changing from a snap back to a strap-back in each scene he's wearing it. (00:10:00 - 00:13:00)
Fresh Prince After Dark - S4-E9
Visible crew/equipment: In the episode where Hilary poses for Playboy, Hilary's strap-on mic is visible on the back of her red dress when she, Will, and Carlton first enter the Playboy party. It is gone in subsequent scenes.
Burnin' Down the House - S6-E1
Continuity mistake: Right before Will pours the liquid into the pot, you can plainly see a fire extinguisher on the counter behind him. It's gone when the fire is actually burning.
Burnin' Down the House - S6-E1
Continuity mistake: The cognac bottle is almost empty when Will passes by the counter, but when he turns around to pour the liquid, the bottle is full.
Answer: No, it's not Whoopi Goldberg herself, just like that's not Prince or Ray Charles. The limo is filled with celebrity impersonators, but they're all uncredited and I could find out who played them.
Bishop73