When Paige asks Leo if the smoking candle is ready, he says it only needs to set and we see that the wax was only just poured. A few moments later we see Leo taking inventory of the arsenal they have just put together and not only is the candle set, it has been removed from the holder/mold.
As Piper begins labor, her new step mom stabs her father in the lower left quadrant of his stomach. We continue to see this until after he saves the day by throwing the demon off the stairs. From that point on, including a scene where Leo heals him, the stab wound is now in the same quadrant but in his back. This is because the blade goes all the way through his torso, as shown by the amount of blood on the long blade after he has been stabbed.
Cronyn hands Phoebe his business card and tells her that his phone number is on the back. In the few quick glimpses of the back of the card in Phoebe's hand - there is nothing written on the back.
When Paige and Phoebe first meet the Unicorn in the kitchen, the person holding the unicorn can be seen under the counter.
When the unicorn is in the kitchen, you can see the string on the horse's head that holds up the horn.