When Joey says the line, "I'm gonna get back to my bucket," there is a very loud stifled laugh immediately after that was picked up by the set boom mics that was likely one of the cast or crew cracking up off-screen at the line, and not one of the audience members who are picked up by more distant room condenser microphones.
When Rachel shows the others Monica's nude photo, she briefly flashes it in view of the camera. The person in the photo is not Monica, but a shirtless man in nude boxers with long hair like Monica's
The books mentioned by Phoebe are "Wuthering Heights" by Emily Brontë and "Jane Eyre" by Charlotte Brontë.
The KFC bucket Joe holds has "Finger Lickin Chicken" slapped over the Colonel. This is because real logos often have to be blurred or removed in cable tv if the producers do not obtain the rights to show a product. KFC's slogan Finger Lickin Good is trademarked so they had to change the last word to chicken to avoid legal damages.