Piper tells Billie "Forget it, Jenkins. It's Chinatown" is a play in the iconic movie line "Forget it, Jake. It's Chinatown" from the 1974 movie Chinatown
This is the third episode in the series that has a plot dealing with Chinese mythology and culture. The first being episode 1.04 "Dead Man Dating", and the second being episode 4.03 "Enter the Demon".
The Chinese sign in the window of the laundry should be a mirror image of itself (like the writing in the window). Instead it is identical to was seen in the bottom of the cauldron.
Henry asks why Paige doesn't use magic to save the world, perhaps Paige was going to mention they tried last year with Avatars but things didn't add up so they had to reverse it. But Henry got a call from a parolee
Chinese zodiac in order: Rat, Ox, Tiger, Rabbit, Dragon, snake, Horse, Goat, Monkey, Rooster, Dog, and Pig. Chinese New Year will begin Jan 25, 2020.