As far as the realism, I am not some hardened ex convict, but the whites pulling off that hit is probably the most realistic of them all, I mean the timing thing is one of those tv show things, but the rest....the dudes who did the hits are probably lifers, or close, and are running the prison, they have nothing to lose but respect and comfort, if they don't act at the behest of the shot callers. I've read books on the Mexican Mafia, and they even got the flop house motel sit downs with the pizzas and beer right.
As far as the Hank thing, and everyone questioning whether the book would be left the bathroom, for one, it's a damn book, not a picture, two, Walt may have forgotten all about it, Skylar could have put that in there, or someone else, or Walt could have just forgotten it one day, there has been so much tension and hectic events in that families life, why wouldn't an oversight like that happen? Additionally, wasn't that in the master bathroom anyway? Walt could have left that in there months ago. Or, just the other day.