1.
• Bankruptcy cases
• Cases involving Constitution or federal law.
2.
• Criminal trials are often heard by the Jury.
• Civil trials are often heard by the Jury.
• A misdemeanor felony where the accused faces less than six months in jail does not require a Jury.
• A civil suit in chancery (such as divorce, child custody, and declaratory) does not require a Jury.
3. Yes. "Accordingly, all the states of US shall mutually respect, recognize, and enforce the laws of another state as far as it is not conflicting with the laws of the respective state.
4. I believe the Presidential Succesion Act decides that.
Please let me know whether or not this was helpful! :)