In most cases it is a violation of the law. But there are exceptions. It is best to check with local law authorities.
That depends on what charges are on your juvenile record.
No
No
Yes
Usually not, however, that will vary from state to state. Most Juvenile records are sealed once he/she becomes an Adult.
Assault and vandalism.
He becomes your mom
jail
Yes, it can. Juvenile records are only sealed from the general public - NICS and law enforcement agencies can still access them.
It depends on how the court wants to try you. Depending on how the court tries you, depends on what happened (i.e. was the gun just drawn, was the gun fired, was someone harmed, was the gun in illegal possession, etc.)
Then that minor would have assault charges and brought to juvenile detention where they would have to go through juvenile court.
If conviction was for an offense that would have been a felony if committed by an adult, then no.