If she doesn't know where or when to go, how does she know she needs to go? The question seems confusing.
She needs to go to court to show responsibility. She or her parents need to find out where court is. Juvenile cases aren't public, so you might have a hard time finding out.
He needs to get a good lawyer. If what you and he say is correct, somebody's lying, so he needs to defend. Don't count on the rubic "If I didn't do it, it'll be okay." Ask the convicted innocents of America.
This is admissible evidence. You weren't questioned so Miranda does not apply (Fifth and Sixth Amendment). There is no reasonable expectation of privacy in the back of a patrol car (Fourth Amendment; but some state laws might prohibit it). Police have been doing this ever since there have been portable recorders, and they regularly catch people in the trunk talking to each other. Even if you were Mirandized, it wouldn't matter because there was no "custodial interrogation."
Check the parole board's website. Federal law allows the states to adopt procedures where persons can petition the governor for a restoration of gun rights, and Florida may be such a state. It is something less than a pardon. In some states, the governor is relatively free with gun rights restoration for hunters only. You need to check your state law.
The courts and lawyers are obligated to tell you the statutory range of punishment. Just because it says life, it doesn't always mean life. Why would you doubt the lawyer? Just check the statute on the internet.
After the fact for permission, no. The larger question is drug testing at all. Private employers have the right to drug test employees as a condition of working there; it you don't like the invasion of privacy, don't work there. The constitution does not apply to private employers. If the nature of the work makes suspicionless drug testing appropriate, then they likely can't be sued for invasion of privacy. It is fact dependent. For example, Office Depot, Lowes, and Home Depot are well known...