Regarding 2: You're correct, the main order book is public and usually anonymous. There are also non-public books called dark pools where you cannot see what other people are bidding. You are also correct in supposing that a lot of meta-games go on, but dark pools don't remove this entirely; they just change the rules. For instance you could, if it is allowed, submit a tiny orders in increasing price until it gets filled; then you know something about the price in the pool.