When Charley's mom's minivan was rear-ended after they had stopped, both of the van's front airbags deployed. Airbags are specifically designed NOT to deploy during a rear impact. Furthermore, the people would not be thrown forwards into the airbags, but thrust back into their seats.
When Charley stakes Ed, the special effect of smouldering into a pile of ash is highlighted with cinders floating in the air. Several are clearly in Charley's face, in his eyes, etc. but he does not react at all.
Just after Jerry tells Charley that he has to stake a vampire through the heart, Jane, Charley's mom, stabs Jerry with the staked Realtor's sign. The POV is looking at Jerry and seeing Jane behind him, driving the stake into an area in the quadrant of his upper left chest and shoulder. But from then on, as Jerry twists around with the stake running through him, it's obviously through the middle of his torso - probably a direct hit on his heart.
When Jerry is going past the security desk, the scene is playing out on the security monitors with Jerry's image removed. When the guard confronts Jerry, the video of him falling down is delayed a few seconds from what's going on. Many newer security systems are DVR (or web) based, which introduces a delay of a second or two between what the camera captures, and what is displayed on the monitor.