1. There's no possibility to get the case transferred to high court or any other court.
If the delay is inordinate or if he's trying to drag it unnecessarily then you can approach high court with a petition to direct trial court to dispose the case expeditiously.
2. A twelve years old child's opinion will be sought by court with regards to his choice to choose either parent.
3. See the first answer
4. The court will be concerned about the child's welfare.
5. You cannot get this case transferred to high court.
6. There's no provision in law for high court to try the case directly.