No such thing as a bad question. I'll ask this one for you before you have to

2:But what separates the Captain from the FO if they are both flying? Why can't the FO actually log it as PIC?

Answer: Because the captain is the person that signs for the aircraft. He is the designated one to be the final decision and accept responsibility for all operations of the aircraft. Therefore while you might perform the same duties within operations of flight, these duties happen under his command. You are a required crew member so any time you are performing the actions of a crew member you may log it as SIC. Only when you have your PIC type rating and are the one that signs for the aircraft may you log it as PIC.