You can open any substance file in the Player, whether or not B2M is installed. It's just the default program in which any substance, B2M included, are opened.
Yes, updates will come to Steam automatically as they are available. Pretty much, yes. The displacement in most substances is by default a plain grey image and the "Relief Balance" parameter allows you to put details in it, from low frequencies only, to higher frequencies, to keep a smooth displacement. You can export…