Let's see:
1)Smith illegally provided licenses,
2)Smith was going to testify in Federal court,
3)Smith dies in a flaming car crash the day before she is to testify,
4)Traces of gasoline are found on Smith and in her car.
The suspects are not being charged in her death.
They'll get six months probation for trying to obtain the licenses
As I recall, Smith was the only one of the 6 charged who was out on bail. The other five were in custody at the time of her death. So unless the hit was directed from a jail cell (unlikely), they are not guilty of (this particular) murder. In fact, Smith's murder was probably intended as an object lesson for the five in custody--something for them to think about when tempted with plea bargains or promises of immunity.
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.