More generally, though, anybody else just not able to ship things they've never seen on screen? I just can't see my way to doing that, even things I might want to ship. But I am basically cannon's bitch.

You're not alone! I'm exactly like that. I don't ship unless the writers put it on screen, clearly. Maybe it is a way to respect the writer's work or to reject the gnawing need for romantic relationship apparently required in every fangirl...