Good list of stuff to have on your mind, for sure. A few things though, from a guy who has had a Model 3 Performance for almost 4.5 years now and nearing 60k miles with it:
Phantom braking is massively overblown as an issue. At least for me. Newer Teslas have different equipment on them but I can tell you I haven't had an instance of unexpected braking while on TCC or AP in over a year now, and I use them a lot. When it was happening before software updates helped iron it out, you could learn (you as a human, I mean) when it might occur based on certain surroundings.
There are service centers in Iowa. One opened up around a year ago in Urbandale and there's one in Council Bluffs.
http://www.tesla.com/findus However, the vast majority of Tesla's service work is done via mobile rangers that come to you/your car wherever you are.
Cost to put a good charger in your garage isn't too bad. Think I paid an electrician here in Waukee about $1,200 to install a new box in my garage and hook up the charger and garage heater I had.
Cold weather definitely impacts range but when you can get a full charge overnight it isn't a big deal. If I'm at 300 miles of range when I leave in the morning, on a bitterly cold day I could maybe get....220 miles of actual driving, or so? But that's plenty for daily use.