1st theory: The Freddy in the car with Abby is Mike possessing a Freddy suit.

Here me out.

In this scene you see someone get dragged away. (with blood I think) Away way I think this is the security guard from the first trailer getting killed.

This scene you see Mike get strap to a chair. I know some people say this could be the other security guard and they are trying to trick us into thinking that it is Mike. But I think it is Mike.

Before the scene he is strapped in the chair (if that is him) he screams and probably and put in that chair.

This scene is when Mike is still strap to the chair and this Freddy type thing happens to him.

This thing kills and stuffs Mike in the suit then he possesses the Freddy suit and takes a taxi with Abby.