1) Sure. That was brought to his attention, and he acknowledged that. And it was also said to him that he cannot be the player who hops around looking for the greener grass. Awareness that he echoed himself and then how he asserted his answer later was noteworthy to me.
2) He has, yes. And yet he targeted the Cardinals for where he wanted to play. Last I checked, the Cardinals and their fan base were having a bit of a crisis of identify because players weren't coming here, weren't falling in love with the tradition, history, etc. etc., and here's a player who has -- who has come for that purpose, who sought out the Cardinals because of all things the Cardinals think they are, and all things the fans want them to be, and you don't believe it? Huh. Maybe just enjoy the fact that a baseball fan, which Arenado, saw in the Cardinals want you want to see in the Cardinals, too. And that he has publicly and privately that the fans are part of that. Take a compliment.
3) Turner is 36. That deal had more to do with his age than any grand strategy. The Dodgers wouldn't let 39-year-old Justin Turner get in the way of a better third baseman. Just saying. You outlined the reasons why yourself.
4) The Cardinals are allergic to "rebuild situation." They've said as much. There is no evidence they or their fan base has the stomach for it.
Don't give them the excuse or soft landing of a rebuild situation if they struggle these years.
Those are my thoughts.