Yes I think these diagrams are pretty accurate. In the first one though, the server can slide a bit more to his right to cover even more of the sharp CC return.
I tried to put the server in the spot where I think that they normally do cover. I've not known a server to serve and then go stand outside of the doubles alley though I agree by the diagram that they could do so to take away more "winner" returns. I just don't see servers actually setting up any wider than what I put on the diagram. To me if the net player doesn't slide over to cover the alley then the seving team is basically just playing the I formation and its a complete and total waste. Actually... let me put together a diagram of where I think that the net player shoudl be set up if the team is in the switched formation (australian) to make it more obvious how out of position I think the net player is where you want them.
I think that I likely step over even further than that... You have your net player just a couple steps away from where I would put them in Australian formation. I am just a huge believer in sliding aggressively to adjust for the angles.
REally it just comes down to whether you think that the net player will be able to put away enough balls to compensage for the number of times they are taken down the line into the open court for a winner. Personally I think its suicide to leave that much court open but that very well could be because I have a loopy topspin forehand and thats a ball I always will look to drop down the line if the net person doesn't slide over enough.
I just can't understand why people would choose to give away the down the line return when thats the easiest return for people who get to the ball late.