Revealing mistake: When Draven sends T-bird to his death in his car, the real Ford Thunderbird is replaced by a fake mockup using a flimsy one-piece fiberglass body mounted on a pair of straight axles. When it explodes, the body lifts off in one piece, warping wildly while the front axle simply falls away. No proper car components like engine, transmission, suspension and so on, are seen anywhere, though they should be. (00:57:05)
Continuity mistake: When Darla prepares breakfast for Sarah, the bottle of juice on the table changes positions between the shots. (00:58:50)
Continuity mistake: The can Albrecht drops on the floor when Eric visits moves places without anyone touching it. When Eric says about the hat still being on it's on the wooden flooring. When he walks past to read the file a few minutes later the can is on the carpet. (00:43:25)
Continuity mistake: When Sarah is skateboarding, and the guy in the car yells at her to get out of the road, she pushes with her right foot and has her left foot in front (a "Regular" stance), but in the next shot she is riding "goofy" stance (right foot front), with no time to change stances. (00:24:25)
Continuity mistake: Top Dollar shows a snow globe to a female companion near the start. Her grip on the snow globe changes instantly. In some shots she has her fingers on the glass and not in others. (00:23:35)
Answer: There is no explaination given in the films, they are just brought back when the crow feels it is the right time to avenge their murder.