In the sitcom scene, a prop holding the brothers bags is next to the window near the door. This item disappears for the stunt where Castiel is thrown to the wall, but is back once Castiel is on the floor.
The very first shot of the brothers getting out of the impala at the Old Mill shows that the car is dry. The car is then immediately seen covered in water droplets in a different camera angle.
As they are examining the body in the procedural cop show, a close up of the victim's head shows a yellow #12 evidence tag close by, but there is no #12 tag in any of the wider camera angles.
As the game show host exclaims "Nutcracker!!" just after Sam gets hit, we can see the assistant on the right reach into a compartment to get the bag of shrimp chips. After the rapid replay of Sam's hit from different angles, the assistant can be seen walking to the compartment for the chips once again.
Water doesn't put out an oil fire; in fact, dousing an oil fire with water will only make things worse. (This is why fire extinguishers that are filled with water can only put out wood/paper fires.) Holy fire, however, does not follow the same rules as normal fire. Once lit, it can burn forever without any additional fuel source, and can be put out quite easily by someone not trapped within.
In the Nutcracker game show scene where Sam gets his nuts cracked we see Dean put his left hand to his mouth in shock but when it cuts away and cuts back to Dean a moment later his right hand is covering his mouth in shock.