If a divorce occurs after an incident, the spouse can be required to testify. In other words, it applies to being married at the time of testimony, rather than the time of the incident. A spouse can voluntarily testify anytime. It is merely a privilege that can be invoked, similar to the Fifth Amendment right to not incriminate oneself. Check with your attorney for specifics.
Home is worse.
To try and control the parents who are making major mistakes. To exact revenge on one or both parents. Number 3 has the worst consequences and is the hardest to overcome. Try to get her parents to study the Goodkids paper and adapt a strict but fair attitude with her. If that fails, or even if it succeeds, you must get her into a counseling program.