I find it doubtful that Memphis DMV was the only place the scam was run. IMHO, the main motive for Smith's murder was to preserve an ongoing operation.
The way I read the article was this: All were arrested on February 5th. All were released on bail (her crime was more severe and she was released, why not the others?). She was to testify later that month, yet was murdered the day before. The prosecution argued to deny bail on the other defendants based on her death. If they were in jail at the time, why would the prosecution argue this way?
Killing her to teach a lesson would make sense if not for the fact that one of the defendants is expected to testify following his guilty plea well after the "lesson" was taught.
As I understood it, she was released and killed in the same day.
One of the jailed men was the mediator in this exercise. He had negotiated this same type of transaction before and gotten away with it. He was also the owner of the car that mysteriously burst into flames before hitting a pole (as observed by witnesses). So one of the jailed men (or his friends) did have access to duplicate keys needed to arrange a device in the backseat/trunk.
This same scam was also discovered in Illinois and other states with other participants.
While the jailed "suspects" (apprehended red handed in the parking lot after the deal went through) claim that they needed the licenses "for to drive the delivery vans of American employer, yes" I think that more licenses were obtained than suspects (meaning that they obtained multiple identities).