Most visa offices end up returning the "proof of relationship" things, but don't assume you will get anything back and keep that in mind when preparing your application.
For cards, I made a photocopy of the inside of each one and added a photo of the outside. Yes, I took photos of the cards. Felt kinda silly for it, but I wanted them to actually see the card.
I sent copies of phone bills simply because after being saved for a couple of years, my phone bills were a bit raggedy. lol. For the boarding passes, I sent the originals, but kept a photocopy at home, just in case I ever had to show it.