1,4 - Virgin is superior to CO in both BF (upper class) and coach, and they have an economy plus section that is not allocated to CO codeshare passengers.

2,3 - The only virgin clubhouse accesible to CO passengers is the one in Newark terminal B. In London, with an upper class ticket you might be able to sneak into the clubhouse although CO is using another lounge which is not as good.

5 - Chances are slim because it is a codeshare and the metal carrier passengers have priority over you. It mainly depends on the load factor in the flight.