1. Assuming both ports are populated with optics
xe-0/1/0
xe-0/1/2
2. Assuming all ports are populated with optics
ge-0/1/0
ge-0/1/1
ge-0/1/2
ge-0/1/3
3. Yes
4. Yes. Unfortunately newer switch hardware (ex4300, ex2300) does not allow you to use PIC0 copper ports or 1Gb SFP ports as VC ports, as the EX4200 allows.